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Control & operations

Real-time control, actuation, protection, alarms, operator UX and the control architecture of the Kronos machines. 581 pages

Access Control and Anonymization

Access control governs who can read or change data; anonymization removes identifying detail so data can be shared more openly.

Access Control: RBAC and ABAC

Access-control models decide whether a principal may perform an action on a resource, from coarse role grants to fine-grained attribute rules.

Accessibility and Colorblind-Safe Design

The control room must work for every operator on every shift: redundant encodings, sufficient contrast, and legibility that does not depend on color vision.

Action-Gating Pipeline

Every candidate action passes a fixed, ordered sequence of independent checks; any stage can reject, and rejection is the default.

Actuator Allocation Across Coupled Systems

Both machines have more actuators than control objectives; Kronos's MPC allocates effort across coils, heating, fueling and DEC to meet goals with margin.

Actuator Command Arbitration

When multiple controllers request the same actuator, L1 arbitrates by fixed priority so protection always outranks optimization.

Actuator Commissioning and Characterization

Before an actuator can be trusted in a loop, its real response, limits, and quirks must be measured and modeled.

Actuator Interfaces

Actuators turn control commands into physical action; the interface must convert, amplify, and safely drive them while confirming what actually happened.

Actuator Management and Allocation

Mapping many competing control demands onto a limited set of shared, constrained actuators without violating hardware limits.

Actuator Saturation Management

Every actuator has limits; managing saturation keeps a loop stable and honest when it runs out of authority.

Actuator Sharing and Allocation

Many control goals compete for the same limited actuators; allocation decides who gets them, when, and how much.

Actuator Sharing and Control Arbitration

Many control goals compete for the same limited actuators, so an arbitration layer allocates them by priority and respects hard limits.

Adaptive Control

Adaptive controllers adjust their own parameters online as the plant changes, maintaining performance without a fixed model.

Adjoints, Hermitian, and Unitary Operators

The adjoint (dagger) is the conjugate transpose; Hermitian operators equal their adjoint, unitary operators have adjoint as inverse.

AI-Native Control Architecture

The Kronos AI-native control architecture — eight layers (L0-L7), a four-phase build with Phase 1 complete, an owned GPU HPC fleet, a 50-100ms predictive shadow, and a hardware-enfor

Air Gaps and Controlled Bridging

The safety and control core is air-gapped from routable networks; the rare crossing to update a model or policy is a deliberate, two-person, fully logged event.

Alarm Flood Suppression and Dynamic Shelving

During an upset one root cause can trigger hundreds of correlated alarms; suppression logic collapses them so the operator sees the cause, not the cascade.

Alarm Management and Rationalization

Applying established alarm-management principles so every alarm is meaningful, prioritized, and actionable — never a wall of noise an operator learns to ignore.

Alerting and Triage UX

Turning anomaly detections, precursors, and interlock events into a ranked, deduplicated, actionable stream an operator can work top-down under pressure.

Ambipolar Potential Control

The electrostatic potential profile confines the burner's central cell; L1 regulates the ambipolar potential through plug conditions to hold axial confinement.

Annotation and Collaborative Markup

Shared, persistent annotations let the crew point at the same thing, capture judgment, and hand off context across shifts and between control room and mobile.

Anomaly and Precursor Timeline UX

A shared timeline that shows precursors emerging, growing, and resolving — turning the anomaly ensembles' outputs into a story an operator can read.

Anomaly Detection from Telemetry

Catching the fault you did not enumerate - unsupervised detection of behavior the plant has never shown before.

Anomaly Detection on Machine Subsystems

Unsupervised models learn normal behavior of machine subsystems and flag deviations that may signal faults before they cause failures.

Anomaly-Detection Ensembles

No single detector is reliable enough for safety-relevant precursors, so Kronos combines reconstruction, density, and forecasting detectors into a calibrated ensemble.

Anti-Windup

Anti-windup schemes prevent an integrator from accumulating error while the actuator is saturated, avoiding large overshoot and sluggish recovery.

Architecture First Principles

The invariants every design decision must respect — separation of latency classes, physical safety floor, bounded intelligence, and traceable data.

Artificial Intelligence

The field of building systems that perform tasks normally requiring human intelligence, from perception to reasoning and control.

Assurance Case (GSN) + Signed Ledger

A structured claims-to-evidence safety argument, and a tamper-evident record of every decision.

Audit and Compliance View

Every operator action, alert, override, and model version is recorded in an attributable, tamper-evident timeline that supports regulators, reviews, and trust.

Backpressure & Flow Control

When a consumer cannot keep up, the system slows producers or sheds non-critical load instead of dropping safety-relevant events.

Backpressure & Flow Control

The fabric manages telemetry flow so a burst never drops safety-critical data, prioritizing channels and applying backpressure to the rest.

Backstepping

Backstepping builds a stabilizing nonlinear controller recursively, treating intermediate states as virtual controls step by step.

Balance-of-Plant Control

Beyond the reactor core, a fusion plant needs cooling, power distribution, and auxiliaries, all coordinated by a plant-wide control system.

Beam Notching for Fast Protection

Cutting or notching neutral-beam power within microseconds removes drive from an evolving instability, a fast reversible protection actuation on both machines.

Block-Encoding of Operators

Embedding a non-unitary operator as a sub-block of a larger unitary, the interface that modern simulation algorithms are built on.

Breakdown and Start-Up Control

Breakdown is the moment the gas becomes a plasma; control must reliably initiate and grow the discharge from nothing.

Breeder (Hyperion) Control-Room View

The operator surface tuned to the spherical tokamak's hard problems: equilibrium reconstruction, the ELM-free negative-triangularity shape, and disruption avoidance.

Breeder Control Problems

For Hyperion, the spherical-tokamak challenges are equilibrium, holding the negative-triangularity ELM-free shape, and disruption avoidance.

Breeder Disruption Mitigation Reflex

When a disruption becomes unavoidable, the breeder reflex converts it from an uncontrolled event into a mitigated shutdown within the plasma's own timescale.

Breeder Sensor-to-Actuator Map

For Hyperion, each control objective is a chain from a diagnostic set to a physical actuator, with the twin and MPC in between.

Breeder Shot Lifecycle

One tokamak shot from arming to post-shot analysis, and the control decisions the stack makes in each window.

Buffer

A buffer passes its input to its output unchanged, restoring signal strength and adding controlled drive or delay.

Burner Control Problems

For the tandem mirror, the challenges are end-plug density, the ambipolar potential, and steering charged particles into the direct-energy-conversion train.

Burner Plug & Potential Telemetry

The burner's control problems live in the end plugs — density and ambipolar potential — and this telemetry set is where the fabric watches them.

Burner Plug-Stability Reflex Supervisor

The burner's end-plug confinement rests on operating conditions far beyond any built device; the reflex supervisor treats every plug excursion as a hard limit, not a setpoint to ch

Burner Sensor-to-Actuator Map

For the burner (Aegis / MetroVolt), the control chains center on the end plugs, the ambipolar potential, and the direct-energy-conversion train.

C3X and C4X Gates

The three- and four-control NOT gates, the small fixed cases of the multi-controlled X most often synthesized directly.

Calculus of Variations for Control

The calculus of variations finds functions that minimize integral cost functionals, the mathematical foundation of optimal control.

Canary Rollout of Control Policies

A canary policy gains narrow, bounded authority — small setpoint deltas inside tight envelopes — that widens only as monitored performance holds, with instant revert on breach.

Carry-Save Adder

A carry-save adder sums three numbers into two without propagating carries, deferring the single slow carry step until the very end.

Cascade Control

Cascade control nests a fast inner loop inside a slower outer loop so the inner loop rejects disturbances before they reach the primary variable.

Checkpoint/Restart and Fault Tolerance

Checkpointing periodically saves a job's state so that after a failure it can restart from the last save rather than from the beginning.

Checkpointing and Fault Tolerance

How long-running Kronos simulations and training runs survive node failures without losing days of compute.

Class Imbalance and Rare Events

Why disruptions and other rare plasma events break naive accuracy, and how to train and evaluate honestly around them.

Closing the Design Point

Closing a design point means every physics, engineering, and safety constraint is satisfied by one consistent set of parameters at the same time.

Cloud and On-Premises HPC

HPC runs both on dedicated on-premises clusters and in the cloud; each fits different needs for scale, latency, cost predictability, and control.

Code Review for Science

A second reader catches faults that authors are blind to, and turns private correctness into shared, defensible correctness.

Coil Power-Supply Switching Control

Fast switching supplies drive the coil currents both machines depend on; L1 controls their switching deterministically to deliver clean, bounded current.

Color Grammar in the HMI

One disciplined, colorblind-safe color system across every operator surface so a color always means the same thing and alerts are never lost.

Command Authorization & Tokens

Every command carries a scoped, short-lived, single-writer token; actuators reject anything unsigned or out of scope.

Commissioning and Safety Validation

Before a safety layer guards a real plasma it is proven by fault injection in hardware-in-the-loop, so the failsafe is validated against faults, not assumed to work.

Computing for Licensing Evidence

Producing the traceable, reproducible analyses a regulator needs to evaluate a plant's safety case.

Computing for Quench Analysis

Modeling what happens when a superconducting magnet loses superconductivity, so the stored energy is dumped safely.

Computing for Safety Analysis

Modeling what could go wrong, how likely it is, and what the consequences would be, to show the plant is safe by design.

Computing for Safety and Licensing

Regulators require evidence, not assertion; computation produces the traceable analyses and records that a licensing case is built on.

Condition Number and Convergence

The ratio of largest to smallest curvature controls how fast first-order methods converge and why ill-conditioned problems crawl.

Confounding and Controls

A confounder is a hidden common cause that fakes a relationship; controls are the methods that strip its influence away.

Context Switching

A context switch saves one task's processor state and restores another's; its cost and predictability directly affect real-time timing budgets.

Continuous Control

Real-valued action spaces demand methods that output continuous commands rather than choosing from a discrete menu.

Control Actuator Inventory

The hardware the control stack can command - coils, power supplies, heating, current drive, and fueling - and each one's character.

Control Allocation

Control allocation distributes a commanded virtual control among redundant actuators, respecting their limits and secondary objectives.

Control Allocation Methods

The mathematics of distributing control demands across redundant, constrained actuators - pseudo-inverses, weighting, and optimization.

Control and Safety Architecture Overview

Kronos's safety architecture is layered defense: bounded reflex, hardwired interlocks, an ML-independent failsafe, and human oversight, each able to hold the line alone.

Control Electronics

Racks of fast digital-to-analog and analog-to-digital hardware generate qubit pulses and digitize readout, synchronized to picosecond precision.

Control Latency Budget

The latency budget accounts for every microsecond between a measurement and the resulting actuator response, and must fit inside the loop period.

Control Loop Fundamentals

The feedback basics - error, gain, stability, and bandwidth - that underlie every plasma control loop.

Control Loop Latency Budget

Decomposing the real-time path into sense, transport, infer, decide, actuate - and the fallback taken when any stage overruns.

Control Room Human Factors

Human factors design shapes displays, alarms, and procedures so operators make good decisions under time pressure and complexity.

Control Safety Integrity Levels

Kronos grades each control function by the consequence of its failure and matches architecture, redundancy, and independence to that grade.

Control Stability and Phase Margin

A feedback loop is stable only if it does not build up oscillations; phase and gain margins quantify how much delay or gain error it can survive.

Control Systems

A control system measures a plant, compares it to a target, and adjusts actuators to drive the difference toward zero.

Control Systems Overview

A control system drives a physical process toward desired behavior by shaping its inputs based on goals and measurements.

Control Theory

The mathematics of steering dynamic systems toward desired behavior using feedback.

Control Unit

The control unit decodes instructions and generates the signals that steer the datapath through each step of execution.

Control Variates

Control variates reduce Monte Carlo variance by subtracting a correlated quantity whose expectation is known and adding it back.

Control-Loop Timing

A control loop must sense, compute, and actuate within its period every cycle; the choice of period couples timing engineering to control theory.

Control-Loop Timing Math

Loop period is not chosen by convenience; it is derived from the closed-loop bandwidth required to stabilize the fastest mode the loop must control.

Control-Oriented Modeling

Control-oriented models capture just enough physics to predict the input-output response controllers need, fast enough to run in real time.

Control-Plane Isolation and Integrity

The safety-critical control plane is isolated from general networks; only validated, one-directional interfaces cross into it, protecting deterministic operation.

Control-Room Decision Support

Software that helps operators understand plant state and choose actions, without taking safety-critical control away from hard interlocks.

Control-Room Layout and Ergonomics

The physical arrangement of the video wall, operator consoles, and roles — designed so information reaches the right eyes at the right distance.

Control-System Verification

Proving that control and protection software behaves correctly across all conditions, including the rare ones that matter most.

Controllability

A system is controllable if the input can drive its state from any starting point to any target in finite time.

Controllability and Observability

Two structural properties defining whether a system can be fully steered and fully inferred.

Controllability and Observability Gramians

Gramians quantify how strongly states can be reached by inputs and seen by outputs, grading the degree of controllability and observability.

Controllability and Observability in Plasma Control

Two structural properties that decide whether a plasma quantity can be driven by the actuators and inferred from the sensors.

Controlled Shutdown and Safe States

The always-available path to a defined low-energy configuration - the floor beneath every other resiliency behavior.

Controlled-Controlled-Phase Gate

Applies a phase only to the all-ones state of three qubits, the diagonal cousin of the Toffoli.

Controlled-Hadamard Gate (CH)

Conditionally places the target into an equal superposition, a controlled-U with U equal to the Hadamard.

Controlled-RY Gate (CRY)

Applies a real-valued Y-axis rotation to a target qubit conditioned on the control being in state one.

Controlled-RZ Gate (CRZ)

Imparts a Z-axis phase rotation on the target qubit conditioned on the control, related to but distinct from controlled-phase.

Controlling Both Machines: Breeder and Burner

Kronos operates two very different confinement schemes with one control philosophy, sharing tools while respecting distinct physics.

Copilot Confidence and Uncertainty

Copilots report calibrated uncertainty drawn from twin UQ, retrieval quality, and self-consistency — so operators know how much to trust each answer.

Copilot Latency and the Offline Boundary

Copilots live in the seconds-and-slower advisory regime, cleanly separated from the microsecond control path they never touch.

Copilot Red-Teaming and Adversarial Evaluation

Deliberate adversarial cases probe for envelope-evasion, prompt injection, ungrounded confidence, and forbidden claims before they can reach operators.

Coupling Strategies and Operator Splitting

Operator splitting advances coupled physics one process at a time, a simple scheme whose accuracy and stability depend on how the pieces are ordered and iterated.

Coupling the Twin to Control

Connecting a twin to the plant control system demands strict timing, safety isolation, and clear authority between advisory and active roles.

Cross-Machine Disruption Model

Transfer-learned disruption prediction from the world's tokamak databases.

Cryo-CMOS Control Electronics

Cryo-CMOS moves qubit control and readout electronics into the cold stages of the cryostat to cut wiring counts and heat loads as processors scale.

Cryogenic and Vacuum Feedthrough Interface

Every sensor and actuator wire crossing the cryostat or vacuum boundary passes a feedthrough; the interface owns integrity, isolation, and interlocks.

Cryogenic and Vacuum Safety Interlocks

Cryogenics and vacuum are preconditions for high-field, high-confinement operation; their interlocks gate energization and default closed on any doubt.

Cryogenic Heat Switches

Heat switches turn thermal contact on and off at low temperature, enabling multi-stage adiabatic demagnetization and controlled thermal isolation.

Current-Profile and q-Profile Control

Controlling the current profile controls the safety-factor profile, which sets both stability and confinement in advanced scenarios.

CZ Gate on Tunable Transmons

The controlled-phase gate uses an avoided crossing with a non-computational level to imprint a state-dependent phase of pi.

Dashboards for Operators, Engineers, and the Public

The same data serves different audiences only through different views; matching depth, framing, and controls to the reader is the design task.

Deadline-Monotonic Scheduling of Control Tasks

Where several deterministic tasks share a core, priority follows deadline; a schedulability test proves the fastest safety task always meets its deadline.

DEC Fault Isolation and Ride-Through

The burner's direct energy conversion couples the plasma to an electrical load; the reflex tier isolates load-side faults before they perturb the plasma.

DEC Fault Ride-Through

L1 isolates a faulted collector stage within the deterministic window so the direct-conversion train keeps running through single-stage upsets.

Defense in Depth

Layered controls ensure that the failure of any single defense does not lead to compromise, because an attacker must defeat several in sequence.

Defense-in-Depth Safety Layering

Independent layers with diverse failure modes multiply reliability; the safety case rests on the product of layer failure probabilities, not any single number.

Defining the Fail-Safe State

A trip is only as good as the state it trips to; each machine has an explicitly defined, benign resting state that every failsafe path drives toward.

Denial of Service and Availability

Attacks that overwhelm or exhaust a system to make it unavailable, threatening the one security property control systems value most.

Density Control

Density control regulates how many particles the plasma holds, using gas puffing and pellet injection against pumping and the density limit.

Density Matrices

A density matrix is a positive operator of trace one that describes any quantum state, pure or mixed, including classical uncertainty.

Detached Divertor Control

Divertor detachment spreads exhaust heat over volume by radiation and neutral collisions; control holds the detachment front in a safe location.

Detecting Shadow-to-Plant Divergence

When the plant departs from the twin's forecast, that gap is both a model-drift alarm and a physical anomaly signal.

Detecting Sub-Threshold Magnet-Quench Precursors

Kronos's anomaly ensemble catches the earliest signs of a REBCO magnet quench, below the threshold that would trip protection, so the twin can act before a trip is forced.

Determinism in Real-Time Systems

Determinism is the property that a system's timing behavior is bounded and repeatable, so its worst case can be known before it runs.

Deterministic Network Fabric

Control traffic rides a time-triggered network where every frame has a scheduled slot, so communication latency is bounded and jitter is negligible.

Deterministic Vacuum Interlocks

PLC-enforced vacuum interlocks protect both machines' vessels by making unsafe valve and pump states physically unreachable.

Diagnostic-to-Control Data Pipeline

The data pipeline moves diagnostic signals to the controllers with bounded, predictable latency, the nervous system of real-time control.

Digital versus Analog: The Trade-offs

A side-by-side comparison of the two quantum-simulation paradigms across generality, error control, coherence, and near-term reach.

Digital-to-Analog Conversion

A DAC turns a numeric command into a continuous voltage or current, forming the output stage that lets a digital controller act on the physical world.

Digital-Twin-Assisted Control

A digital twin runs a live model of the machine alongside the real one, supporting estimation, prediction, and validation of control actions.

Dirac Bra-Ket Notation

Dirac notation writes quantum states as kets and their duals as bras, making inner products, outer products, and operators compact.

Direct Converter Electrical Output Control

The high-voltage direct current from a direct energy converter must be conditioned and inverted into stable, standards-compliant electrical output.

Direct Energy Converter Control (Burner)

A direct energy converter turns the kinetic energy of charged fusion products straight into electricity by decelerating them against a voltage.

Discrete-Time Control

Digital controllers act at sample instants, not continuously; discrete-time analysis captures the effects of sampling, hold, and computation delay.

Disruption Avoidance

Acting on early warning to steer the plasma away from a disruption while keeping the discharge alive.

Disruption Avoidance

Avoidance keeps the plasma away from the boundaries where disruptions occur, always preferred over cleaning up after one.

Disruption Avoidance Actuation

L1 arms and fires a graded response to disruption precursors on the breeder, from beam notching and shape trims to controlled ramp-down and mitigation.

Disruption Avoidance and Mitigation

Turning a disruption prediction into an action: steering the plasma away from the boundary or safely shutting it down.

Disruption Countdown and Mitigation UI (Breeder)

When a breeder disruption becomes likely, the interface collapses to a single decision surface: time remaining, options, and the mitigation path — with hardware still authoritative

Disruption Early-Warning Systems

An end-to-end disruption warning system fuses diagnostics, a trained predictor, and a mitigation trigger under strict real-time latency budgets.

Disruption Mitigation

When a disruption is unavoidable, spreading the released energy safely and suppressing runaway electrons to protect the machine.

Disruption Mitigation

When a disruption cannot be avoided, mitigation spreads the energy release and suppresses runaway electrons to protect the machine.

Disruption Mitigation Injection

When a breeder disruption is unavoidable, L1 fires mass or impurity injection on a deterministic trigger to radiate energy uniformly and spare the vessel.

Disruption Modeling

Disruption codes simulate the rapid loss of confinement and current, predicting the thermal, electromagnetic, and runaway-electron loads a device must survive.

Disruption Modeling Codes

Disruption codes model the fast loss of plasma confinement, predicting the thermal quench, current quench, forces, and heat loads on the machine.

Disruption Precursor-to-Actuation Latency Chain

Mitigation only helps if the whole chain from precursor detection to material in the plasma completes inside the disruption's own growth time.

Disruption Precursors in the Breeder

For Hyperion, the anomaly ensemble specializes in the magnetic and kinetic signatures that precede a tokamak disruption, feeding disruption avoidance.

Disruption Prediction

A twin can watch for the precursors of a plasma disruption and forecast its onset in time for the machine to respond.

Disruption Prediction

Prediction gives the control system advance warning of an approaching disruption so it can avoid or mitigate in time.

Disruption Prediction and Avoidance

A disruption is a sudden loss of plasma confinement; predicting the precursors early enough to steer away from them is a core control task.

Disruption Prediction and Mitigation

The breeder's fast-loop resiliency problem: predict a tokamak disruption early enough to soften it, at delta -0.30 and 9.66 MA.

Disruption Simulation for the Breeder

Simulating how Hyperion loses control so the twin can recognize precursors and the failsafe can act before damage occurs.

Disruption-Mitigation Workflow

When the twin predicts a breeder disruption, orchestration triggers a bounded mitigation sequence before the plasma terminates uncontrolled.

Distance and Rate Tradeoffs

A code cannot maximize protection, efficiency, and locality at once, and where a family sits among these competing goals decides where it is useful.

Distributed Control

Distributed control coordinates many local controllers, each using limited local information, to achieve a global objective without a central authority.

Distributed Tracing & Correlation

Correlation and causation IDs thread a single shot's activity across every service so latency and causality can both be reconstructed.

Disturbance Rejection

Disturbance rejection is a control loop's ability to hold the output near its target despite unwanted inputs, governed by the sensitivity function.

DRAG Pulse Shaping

Derivative Removal by Adiabatic Gate adds a quadrature correction to a control pulse so that fast single-qubit rotations do not leak into higher levels.

Dual Control

Dual control balances two competing goals: controlling the plant well now and probing it to reduce uncertainty for better control later.

Duality of Controllability and Observability

Controllability and observability are mirror images: each result about one becomes a result about the other by transposing the system.

Echoed Cross-Resonance

Splitting a cross-resonance pulse into two halves separated by control pi pulses cancels several error terms and isolates the useful ZX interaction.

Economic Model Predictive Control

Economic MPC optimizes a general performance objective directly rather than tracking a setpoint, driving the plant toward the best operating regime.

Edge Compute in Control

Placing computation near sensors and actuators cuts latency and keeps control loops running independent of network and cloud availability.

Edge FPGA Microsecond-Deterministic Actuation

Field-programmable gate arrays at the machine edge execute control logic in fixed clock cycles, giving cycle-exact, jitter-free actuation for both machines.

Edge Preprocessing

Some validation and feature extraction runs at the edge, near the machine, to cut latency and volume before telemetry travels to the archive and twin.

Electromagnetic and Eddy-Current Codes

Electromagnetic codes compute induced currents and forces in conducting structures during field changes, essential for control and disruption loads.

ELM Control and Pacing

Edge-localized modes are periodic edge bursts; control aims to make them small and frequent rather than large and rare.

ELM-Free Regime Control

The negative-triangularity edge suppresses edge-localized modes; L1 monitors edge conditions to keep the breeder in the ELM-free regime it was designed for.

Emulator Error Control

A surrogate is only useful if its own error is bounded and propagated; emulator error control keeps the approximation honest.

End-Plug Density Control

The tandem-mirror burner confines the central cell with dense end plugs; L1 regulates plug density as the machine's primary confinement actuator.

End-to-End Timing Model

The nested timescales the stack must respect, from sub-millisecond plasma control to multi-year campaigns, and how each loop is budgeted.

Engineering Copilot: Anomaly Triage

Ranking, deduplicating, and root-causing the anomaly flags raised by L3 ensembles so operators see prioritized, explained events rather than a raw alert stream.

Error Rates in Quantum Hardware

Error rates quantify how often operations go wrong; their size relative to the fault-tolerance threshold decides whether error correction can work.

Error-Field Correction

Detecting and cancelling small, unintended non-axisymmetric magnetic fields that can lock modes and trigger disruptions.

Escalation and On-Call Workflows

How an unattended or ambiguous condition finds the right human fast — and how the interface makes escalation the easy, recorded default.

Evaluating a Disruption Predictor (ROC)

Score a binary classifier that flags impending plasma disruptions, sweep the threshold, and build the ROC curve with its area.

Event-Triggered Control

Event-triggered control updates the control action only when a state-dependent condition signals that an update is needed, saving computation and communication.

Exactly-Once vs At-Least-Once

The stack chooses delivery semantics per topic; safety-critical commands get effectively-once via idempotency, telemetry tolerates at-least-once.

Exception Handling and Graceful Degradation

A robust control system degrades gracefully, falling back to simpler safe behavior when a sensor, actuator, or computation fails.

Exception Handling in Control

How the stack detects off-normal conditions and branches to pre-validated recovery or termination rather than improvising in a crisis.

Experiment Scheduler with Priority & Preemption

The scheduler allocates machine time by priority, preempts running work for safety, and prevents low-priority starvation.

Explainability & Interpretability

Mechanistic explanations operators and regulators can audit — the "why", not just the confidence.

Explicit Model Predictive Control

Explicit MPC precomputes the optimal control law offline as a piecewise-affine function of the state, replacing online optimization with a lookup.

Fail-Safe vs Fail-Operational

Some L1 functions must fail into a safe state; others must keep operating through a fault. Kronos chooses per function based on which failure is worse.

Fail-Safe vs Fail-Secure

When a system fails, it can default to the safe state or the secure state, and these are not always the same choice.

Failover Architecture

How control authority moves off a failed node, actuator, or model without losing the plant - redundancy that acts within a loop deadline.

Failure Domains & Bulkheads

Orchestration is partitioned into isolated failure domains so a fault in one subsystem cannot cascade into machine-wide loss of control.

Failure Response Decision Table

Every anticipated fault maps in advance to a defined response and a defined safe state, so the reflex tier looks up the answer instead of computing it under duress.

Fault Detection and Isolation

Detecting that something is wrong, then locating which component - the FDI layer that every mitigation depends on.

Fault Ride-Through and Safe Shutdown

When something goes wrong the plant must either ride through the disturbance or shut down safely in a controlled, predictable sequence.

Fault Tolerance

Fault-tolerant design ensures that a single component failure causes at most one error per code block, so errors never cascade uncontrollably.

Fault Tolerance and Failover

A fault-tolerant system keeps functioning despite component failures by detecting faults and switching to healthy resources without violating timing.

Fault Tolerance at Scale

With millions of components, failures are routine; fault tolerance keeps long computations progressing despite hardware and software faults.

Fault-Tolerant State Preparation

Encoding a fresh logical state must itself resist faults, or the errors introduced during preparation defeat the code before computation begins.

Fault-Tolerant Syndrome Extraction

Measuring stabilizers without spreading a single ancilla fault into many data errors requires verified ancillas or flag qubits.

Feedback Linearization

Feedback linearization cancels a system's nonlinearities with a change of coordinates and control, exposing linear dynamics for standard design.

Feedback Loop

A control arrangement where a system's output is measured and fed back to adjust its input.

Feedforward and Feedback Control

Feedforward applies the planned command in advance; feedback corrects the difference between plan and reality. Good control uses both.

Feedforward Control

Feedforward acts on a measured reference or disturbance before it affects the output, complementing feedback's after-the-fact correction.

Feedforward Control in Plant Scenarios

Feedforward uses a known plan or disturbance to command actuators in advance, leaving feedback to correct only the residual error.

Firmware Signing and Secure Update

Firmware and control artifacts are signed, version-monotonic, and delivered through the gated import path, so only authorized, non-rollback updates ever reach the machine.

First-Out and Root-Cause Presentation

In a cascade, showing the first alarm to fire and the inferred root cause turns a confusing flurry into an actionable diagnosis.

Flag Fault-Tolerant Syndrome Extraction

Flag-based syndrome extraction schedules a few ancilla qubits so that any harmful measurement fault is detected, keeping the effective distance intact.

Flat-Top Control

Holding steady plasma conditions during the useful phase of a discharge, regulating current, shape, density, and profiles against drift.

Floyd-Warshall Algorithm

Floyd-Warshall computes shortest paths between all pairs of vertices with a triple loop, in O(V^3) time.

Flux Coordinates and the Safety Factor

Straight-field-line flux coordinates turn the tangled 3D field into simple geometry, and the safety factor q(psi) they yield is the master stability parameter for the breeder.

FPGA vs CPU vs GPU for Control

Each compute fabric has a place in Kronos: GPUs for offline training, CPUs for coordination, FPGAs for the timed control and protection paths.

Fredkin Gate (Controlled-SWAP)

A controlled swap of two target qubits, universal for reversible classical logic and central to the swap test.

fSim Gate

A two-parameter fermionic-simulation gate that captures a tunable exchange plus a controlled phase in one native operation.

Functional Safety and Integrity Allocation

Each safety function gets an integrity target set by the severity and frequency of the hazard it prevents; higher targets demand more redundancy, coverage, and proof.

Gain Scheduling

Gain scheduling controls a nonlinear plant by interpolating a family of linear controllers designed at fixed operating points.

Gas-Puffing Servo Valves

Fast piezo servo valves meter fuel and impurity gas into both machines; L1 modulates flow deterministically for density control and edge management.

Gated Recurrent Unit

The GRU is a streamlined gated recurrent cell that merges the LSTM's memory and gating into fewer parameters with often-similar performance.

Global Phase Gate

Multiplies the entire state by a phase factor, invisible on its own but consequential when placed under a control.

Golden Master Testing

Record the output of a trusted run as a reference, then flag any future change from it; a blunt but powerful safety net.

GPU Occupancy

Occupancy is the ratio of active warps on a streaming multiprocessor to the hardware maximum, a proxy for how well latency is hidden.

Graceful Degradation

When full service is impossible, deliver reduced service safely instead of tripping - the primary lever against the availability gate.

Grad-Shafranov Equation for Control

The force-balance equation that underlies equilibrium reconstruction, and why its structure shapes real-time control.

Grid Frequency Response and Synthetic Inertia

On sub-second timescales the burner supports grid frequency through droop control and direct-energy-conversion-backed synthetic inertia, all bounded by the safe envelope.

Grid Integration: Dispatching Firm Power

The burner housings export firm, dispatchable power through direct energy conversion; L7 is the interface that makes that export legible and controllable to a grid.

Gyrotron Control

A gyrotron is the high-power millimeter-wave source for electron cyclotron heating, and its operation depends on tight control of voltage, current, and field.

H-Infinity Control

H-infinity control minimizes the worst-case gain from disturbances to errors, giving a systematic route to robust multivariable design.

H-Infinity Optimal Control

H-infinity control minimizes the worst-case gain from disturbances to regulated outputs, delivering guaranteed robustness against bounded uncertainty.

H2 Optimal Control

H2 control minimizes the energy of the closed-loop response to white-noise or impulsive disturbances by minimizing a system's H2 norm.

Halo Current and Force Limits

A disruption drives halo and eddy currents through the vessel; the safety envelope caps the forces these can exert on the structure.

Hard Real-Time Bounds

A control action is only correct if it is also on time; L1 treats deadlines as functional requirements with provable worst-case bounds.

Hard vs Soft Real-Time

A real-time system is judged by whether it meets deadlines, not by raw speed; the cost of a missed deadline separates hard from soft.

Hardware vs Software Control

The choice between implementing control in fixed hardware or in software trades determinism and speed against flexibility and complexity.

Hardware-in-the-Loop Testing

Hardware-in-the-loop testing runs real control hardware against a simulated plant, validating the twin and controllers before the machine exists.

Hardwired Interlock Matrix

The interlock matrix expresses which states permit which actions in permissive logic that lives outside software, so no software fault can grant a forbidden action.

Heartbeat and Watchdog Supervision

A watchdog turns silence into safety: any controller that stops proving it is alive causes a trip, so a hung process fails safe instead of failing quiet.

Heating Power Control

Heating power control modulates auxiliary systems to regulate temperature, stored energy, and profiles while respecting source limits.

Helium Refrigeration Cycle Control

A large helium refrigerator uses staged compression, heat exchange, and turbine expansion to reach a few kelvin, and each stage is actively controlled.

High-Performance Computing

Aggregating large amounts of computing power to solve problems too big for a single machine.

Human Factors and Cognitive Load in the Control Room

Designing the fusion control room around the limits of human attention and working memory so operators stay effective during the worst minutes, not just the calm ones.

Human Oversight and Approval

A qualified operator remains the decision authority for every side-effecting action; copilots inform and propose, humans approve and own.

Human Oversight and the Control Room

Automation runs the fast loops, but humans set intent, supervise, and hold authority to intervene from the control room.

Hypothesis Testing

A hypothesis test asks whether data are surprising enough under a default assumption to reject it.

ICE-PISTON Preload Control

L1 sequences the cryogenic ICE-PISTON cycle that preloads the high-field magnets, keeping REBCO strain inside its envelope through cooldown and energization.

ICS and SCADA Security

Industrial control systems supervise physical plant, and securing them means protecting integrity and availability of control, not just data.

Idempotency & Deduplication

Retries are inevitable on a distributed control plane; idempotency keys make a repeated write or command harmless.

Impurity and Radiation Control

Impurity control balances the radiation that protects walls against the core dilution and radiative collapse that too many impurities cause.

Incident Replay and Post-Event Reconstruction

Every shot and every upset is fully reconstructable: synchronized telemetry, twin state, model confidence, alerts, and operator actions replayed on one timeline.

Incident Replay and Postmortem

Turning every fault into a reproducible record and a durable lesson - the loop that makes the stack more resilient over time.

Integral Windup and Anti-Windup

When an actuator saturates, an integrator keeps accumulating error, causing large overshoot; anti-windup schemes prevent this.

Integrated Commissioning of the Control System

Commissioning brings the control system online in careful stages, proving each layer before the next depends on it.

Interconnect Fabric and Collective Communication

The low-latency, high-bandwidth fabric that decides how far Kronos coupled solves and distributed training can scale.

Interconnects

The interconnect is the network binding compute nodes; its latency and bandwidth often decide whether a large simulation scales.

Interferometry for Density Control

How laser interferometry provides the fast, reliable density measurement that closes the density-control loop.

Interlock Integration

Hardware interlocks are the last line of defense and act independently of software; orchestration integrates with them but never replaces them.

Interlock Logic Hardware

Machine-protection interlocks are implemented in dedicated hardware whose safe state is the default, so a failure denies rather than grants dangerous action.

Interlocks and Permissives

Interlocks block dangerous actions and permissives allow safe ones; together they enforce that a system operates only within its safe envelope.

Interpretability and Explainability

Understanding why a model made a prediction, which matters when physicists and operators must trust it.

Interrupt Handling and Latency

Interrupts let hardware demand prompt attention; interrupt latency, the delay before the response begins, is a key determinant of real-time responsiveness.

Ion Cyclotron Heating Control

Ion cyclotron systems heat plasma ions with tens-of-megahertz waves launched from in-vessel antennas, where coupling and matching dominate control.

Isoflux versus Rigid Shape Control

Two ways to frame the shape-control problem: matching flux at boundary points, or moving a rigid outline.

Jitter: Sources and Mitigation

Jitter is the variation in timing between cycles; even when average latency is fine, jitter degrades control quality and complicates timing proofs.

Kinetic and Profile Control

Kinetic control shapes the radial profiles of temperature, density, and rotation rather than just their scalar averages.

Koopman Operator Learning

The Koopman operator recasts nonlinear dynamics as a linear evolution of observables, enabling linear tools on nonlinear systems.

Kraus Operators

Kraus operators give a concrete, computable representation of any quantum channel as a sum of one-sided products.

L1 Control Plane Architecture Overview

The L1 tier is Kronos's hard real-time layer: edge FPGAs and PLCs that convert model intent into microsecond-deterministic actuation for both machines.

L1 · Control Plane

Edge FPGA microsecond-determinism, hard real-time actuation, and the autonomous hardware failsafe.

L1 — Control Plane

Edge FPGAs enforcing sub-10-microsecond determinism, synchronized actuation gates, and the autonomous hardware failsafe that dumps a quench with zero AI dependency.

L3 for the Breeder: Disruption Avoidance

The breeder's highest-consequence event is a disruption; L3 is architected to avoid disruptions early rather than mitigate them late.

L3 for the Breeder: The ELM-Free Negative-Triangularity Shape

Negative triangularity offers an ELM-free edge, but only if the shape is held precisely; L3 makes that a continuous control guarantee.

L3 for the Burner: The Ambipolar Potential

The electrostatic potential that traps the burner's central-cell ions is what L3 must estimate and shape, a control target with no tokamak analogue.

L4 · Orchestration

Event streaming, the workflow engine, the rules engine & safety bounds, and human-in-the-loop routing.

L6 Experience: The Human Interface to Two Fusion Machines

Layer 6 is where operators see, trust, and act on everything the lower layers compute — for the breeder (Hyperion) and the burner (Aegis / MetroVolt).

L6 · Experience

The control-room 3D twin overlays, plant-floor SCADA, and mobile engineering.

Lambda and Kappa Architectures

Lambda and kappa are two blueprints for combining historical accuracy with real-time freshness in one analytical system.

Large-Format Video Wall

The shared control-room display that carries the one common operating picture every role must agree on — legible across the room and resilient to failure.

Laser Control of Qubits

Trapped ions, neutral atoms, and NV centers are controlled with laser light, using resonant, Raman, or Rydberg transitions to drive gates.

Latency and Data-Staleness Indicators

Operators must always know how fresh what they are looking at is; the interface shows data age and freezes rather than extrapolating when a feed stalls.

Latency and Jitter in Control Systems

Why bounded, predictable timing matters as much as raw speed in a real-time plasma control system.

Latency Budget per Interface

Each physical interface carries an end-to-end latency budget from sensor edge to actuator gate, and the budget decides where its loop can close.

Latency Budgets in Real-Time Control

A control loop is only useful if it finishes in time; the latency budget is the discipline that keeps every step inside its deadline.

Latency Fundamentals

Latency is the elapsed time from a stimulus to the completed response, and in control it must be measured end to end, not stage by stage.

Layer 1: Deterministic Hardware Reflexes

The fastest control layer: microsecond trip lines and interlocks implemented in fixed logic that protect the machine without waiting on any software decision.

Layer 4 Orchestration Overview

The orchestration layer coordinates twin predictions and copilot proposals into bounded, gated actions before anything reaches real-time control.

Layer 4: Real-Time State Estimation

The layer that fuses raw diagnostics into a coherent, physically consistent estimate of the plasma state for every controller above it.

Layer 8: Human Oversight

The slowest and highest layer: human operators who set intent, approve exceptions, and make the judgments no automated layer should make alone.

Line Semantics

Three line styles classify every connection by latency class — so the diagram proves that a microsecond command never rides a batch path.

Linear Parameter-Varying Control

LPV control designs one controller for a family of linear models indexed by measurable parameters, guaranteeing performance across the whole operating envelope.

Linear-Quadratic Regulator (LQR)

LQR computes the state-feedback gain that minimizes a quadratic cost trading state error against control effort, yielding a robust optimal controller.

Linear-Quadratic-Gaussian Control (LQG)

LQG combines an LQR optimal feedback gain with a Kalman filter estimator to control a noisy system using only its measured outputs.

Locked-Mode Detection and Control

A locked mode is a non-rotating magnetic island that often precedes a disruption; detecting and unlocking it is a priority for the off-normal layer.

Lustre Striping

Striping controls how many storage targets a Lustre file is spread across and in what chunk size, tuning single-file bandwidth.

Lyapunov Redesign

Lyapunov redesign adds a robustifying term to a nominal controller so a known Lyapunov function keeps decreasing despite matched uncertainty.

Machine Learning for Divertor Heat-Flux Prediction

Models predict and monitor the intense, narrow heat-flux loads on the divertor, informing detachment control and component protection.

Machine Protection Systems

The machine protection system is the last line of defense, acting to protect hardware even when it means abandoning the plasma.

Machine-Learned Disruption Precursors

Classifiers learn the signatures that precede a plasma disruption, providing warning time for mitigation before confinement is abruptly lost.

Magnet Delta-T Quench Precursor

The earliest reliable sign of a quench in a high-field REBCO magnet is a localized temperature rise; L1 senses its rate to trip before a normal zone spreads.

Magnet Energy Extraction and Dump

When a magnet must be de-energized fast, its stored energy is driven into external resistors along a fail-safe path that defaults to dumping on loss of control.

Magnet Protection Interlocks

A hard-wired interlock chain guards the coils, tripping the supply and firing the dump whenever any monitored condition leaves its safe window.

Magnet Quench Detection and Protection

A superconducting magnet that loses superconductivity can destroy itself in seconds; detecting the onset fast is a hard real-time task.

Magnet Quench Protection Model

A quench is a sudden loss of superconductivity; protection systems detect it early and safely dissipate the stored energy.

Magnetic Diagnostics for Control

Flux loops, pickup coils, and saddle sensors - the fast, robust magnetic measurements that anchor real-time control.

Memory Controllers

A memory controller translates a processor's memory requests into the precise timed command sequences that DRAM chips require.

Memory Locking and Cache Control

Page faults and cache misses cause unpredictable delays; locking memory and controlling cache behavior are standard techniques for real-time determinism.

Microsecond Real-Time Lines

The hard-deterministic connections: sub-10-microsecond, jitter-bounded, and the only lines permitted on the safety-critical command path.

Microsegmentation of the OT Network

Beyond coarse zones, every controller pair is placed in its own micro-perimeter, so lateral movement between two OT nodes requires an explicit allow rule that mostly does not exist

Mixed H2/H-Infinity Control

Mixed synthesis optimizes average performance under an H2 objective while enforcing a hard worst-case robustness bound in the H-infinity norm.

ML for Density-Limit Prediction

Learned models estimate proximity to the operational density limit, where excessive fueling drives radiative collapse and disruption.

Model Predictive Control for Plasmas

Optimizing actuator commands over a receding horizon while explicitly honoring the plasma's and hardware's hard limits.

Model Predictive Control for Plasmas

Model predictive control optimizes actuator commands over a short future horizon each cycle, handling constraints and coupling directly.

Model Provenance Badges

A compact, glanceable badge system that tells an operator at a glance whether an AI output is trained, validated, calibrated, and running on healthy inputs.

Model-Predictive Control (MPC)

MPC repeatedly solves an online optimization over a finite horizon, applies the first move, and re-plans, handling constraints directly.

Model-Predictive Control: The Optimal-Control Formulation

MPC plans actuation by solving a constrained optimal-control problem over a finite horizon each cycle, the core planner for breeder shape and burner potential.

Model-Predictive Control: The Optimization

Kronos's MPC agents plan actuation by solving a constrained optimization over the twin's predicted trajectory at every control cycle.

Model-Reference Adaptive Control

MRAC adjusts controller parameters online so the plant output tracks the response of a chosen reference model despite unknown plant parameters.

Model-Reference Adaptive Control

MRAC adjusts controller parameters online so the closed loop matches a chosen reference model despite plant uncertainty.

Moving-Horizon Estimation

MHE estimates states by solving a constrained optimization over a sliding window of recent measurements, the estimation dual of predictive control.

MPC QP Solver Mathematics

A linear-model MPC step is a quadratic program; solving it fast and reliably each cycle is what makes real-time predictive control feasible.

MPI Allreduce

Allreduce combines a value from every process using a reduction operator and delivers the identical result back to all processes.

MPI Reduce

Reduce combines a value from every process using an operator and delivers the single result to one root process.

mu-Synthesis

mu-synthesis designs controllers that are robust against structured uncertainty by minimizing the structured singular value of the closed loop.

Multi-Modal DEC Train Control

L1 coordinates the burner's TWDEC, ultra-high-field MHD, and thermionic conversion stages so each energy channel is captured by the mode suited to it.

Multi-Unit Coordination and Control

A fleet controller coordinates many units through the same unified API each unit exposes, balancing power obligations, fuel, and maintenance across the population.

Multiplexer

A multiplexer selects one of several data inputs and routes it to a single output under the control of select lines.

Multivariable (MIMO) Control

Multivariable systems have coupled inputs and outputs, so each actuator affects several variables, demanding coordinated design.

Navigating the 3D Model

Orbit, pan, zoom, and framing controls, plus the keyboard and touch shortcuts that make the model quick to explore.

Negative-Triangularity Shaping Mathematics

The breeder runs at negative triangularity delta -0.30; parameterizing and controlling that inverted-D shape is a specific geometric problem layered on Grad-Shafranov.

Neoclassical Tearing Mode Control

Neoclassical tearing modes form magnetic islands that degrade confinement; control locates and shrinks them with targeted current drive.

Neural Lyapunov / ISS Certificates

Learned stability certificates for the coupled twin-plus-controller loop.

Neural Networks in Real-Time Control

Using trained networks as fast surrogates, estimators, or controllers inside the real-time loop - with the verification burden that implies.

Neural Operators for PDEs

Networks that learn mappings between functions, approximating the solution operators of the equations governing plasmas.

Neutral Beam Alignment and Interlocks

A neutral beam carries megawatts in a narrow line; misalignment can strike a wall, so aiming and geometric interlocks are safety-critical.

NISQ Reality: Near-Term vs Long-Term

On current noisy devices no fusion computation beats classical; the honest case for quantum is fault-tolerant and years out.

No-Cloning and QEC

The no-cloning theorem forbids copying an unknown quantum state, which rules out classical triple-modular redundancy but not error correction itself.

Nonlinear Control

Nonlinear control handles systems where superposition fails, using tools like linearization, Lyapunov methods, and geometric techniques.

Nonlinear Model Predictive Control

Nonlinear MPC solves a constrained optimal control problem over a nonlinear model at each step, applying the first move and re-optimizing.

Numerical Analysis

The study of algorithms that compute approximate solutions to mathematical problems, with control of error.

Observability & SLOs

The orchestration layer is measured against explicit service-level objectives for latency, lag, and safety-check availability.

Observability and Controllability

Observability asks whether sensors can reveal the internal state; controllability asks whether actuators can steer it.

Observables and Hermitian Operators

Observables are represented by Hermitian operators, whose real eigenvalues are the possible measurement outcomes and whose eigenvectors are the outcome states.

Offline Batch RL from Logged Pulses

Control policies are learned from the logged L0 pulse archive using conservative offline RL, never by exploring on the live machine, where exploration is a fault.

Offline-to-Online RL

Pretrain a policy on logged data, then fine-tune it with limited online interaction, combining safety and adaptability.

One MPC Optimization Step

Solve a single model-predictive-control problem: minimize a quadratic cost over a short horizon, apply only the first control, then repeat.

Ontologies and Controlled Vocabularies

Controlled vocabularies fix the terms used to describe data; ontologies add the relationships among those terms so machines can reason.

OOD Detection & Epistemic Gating

Detect when the plant is outside the training distribution and defer before acting.

Open Loop vs Closed Loop

Open-loop control commands blindly; closed-loop control measures the result and corrects, buying disturbance rejection and robustness.

Operations Copilot: Procedure Generation

Generating startup, shutdown, recovery, and maintenance procedures from approved templates, twin state, and retrieved standing orders.

Operator Abort and Manual Trip

A human can always take the machine to safe state through a path that does not route through the AI, the network, or ordinary software.

Operator Learning and Fourier Neural Operators

Operator-learning methods approximate the solution operators of plasma partial differential equations, generalizing across inputs and resolutions.

Operator Learning Theory

Operator learning studies when and how mappings between infinite-dimensional function spaces can be approximated and generalized from data.

Operator Quantum Error Correction

The operator, or subsystem, framework generalizes the standard correction conditions to allow part of the encoded space to be discarded rather than protected.

Operator Situational Awareness

Designing displays around Endsley's three levels — perception, comprehension, and projection — so operators of both machines always know what is, what it means, and what comes next

Operator Splitting

Operator splitting advances a multi-physics problem by solving its constituent operators in sequence, each with a method suited to it.

Operator Training Simulators

A twin-based training simulator lets operators practice normal, off-normal, and emergency operations on a faithful virtual machine.

Operator Training Simulators

High-fidelity plant simulators that let operators build skill and rehearse rare events safely before the plant exists.

Optimal Control

Optimal control finds the input that minimizes a cost functional subject to the system dynamics, unifying many design methods under one principle.

Out-of-Distribution Signaling to Operators

The single most important trust signal: telling the operator plainly when the machine has entered a regime the AI was never trained on.

Out-of-Order Execution

Out-of-order execution runs instructions as soon as their inputs are ready rather than in program order, hiding latency.

Overlapping Communication and Computation

Overlapping hides communication latency by performing independent computation while messages are in flight rather than waiting for them.

Passivity-Based Control

Passivity-based control exploits energy conservation and dissipation, ensuring stability because interconnecting passive systems remains passive.

Patch Management for Critical Systems

Keeping software current closes known vulnerabilities, but on safety-critical systems patching itself carries risk and must be managed carefully.

Pellet Injection Timing

Cryogenic pellets deliver deep, discrete fuel; L1 times each injection precisely for density profile control, pacing, and disruption mitigation.

Penetration Testing and Red-Team Validation

Security claims are tested by an adversarial team against the digital twin and staging OT, because a control that has never been attacked is only a hypothesis.

Phase-Locked Actuation Commit

When several actuators must move as one, Kronos uses a two-phase commit locked to a shared clock so the group either acts coherently or not at all.

PID and Modern Control in Fusion

When simple proportional-integral-derivative loops suffice and when model-based multivariable control is needed.

PID Control

The PID controller combines proportional, integral, and derivative action; it is the most widely used feedback law and a template for real-time control code.

PID Control Loops in Fusion Systems

The proportional-integral-derivative loop is the workhorse regulator behind coil currents, temperatures, flows, and pressures throughout the plant.

PID Controller

A widely used feedback controller that combines proportional, integral, and derivative terms to correct error.

PID vs LQR on a Mass-Spring

Control a damped mass-spring to a setpoint with a tuned PID loop and with an optimal LQR gain, and compare the closed-loop behavior.

Pipelining Hazards and Forwarding

Pipelining overlaps instruction stages for throughput, but data, control, and structural hazards can stall it unless resolved.

Plant Control State Machines

A supervisory state machine sequences the whole plant through its operating phases and enforces the conditions required to move between them.

Plant-Floor SCADA and HMI

The supervisory control and data acquisition surface for balance-of-plant: pumps, cryogenics, vacuum, tritium handling, and power supplies, rendered for floor operators.

Plasma Control Simulation

Control simulation codes model the plasma response to actuators so shape, position, and profile controllers can be designed and tested before operation.

Plasma Control Simulation Codes

Control simulation codes model the plasma as a dynamic system with sensors and actuators to design and test the feedback that holds a discharge.

Plasma Control System Architecture

A plasma control system links diagnostics, real-time computation, and actuators into feedback loops that hold a discharge on its intended trajectory.

Plasma Control System Architecture

The hardware and software organization that lets many control functions run at different rates while sharing sensors and actuators.

Plasma Control Systems

Confining a fusion plasma requires fast, multivariable real-time control coordinating many magnets and diagnostics within microsecond timing budgets.

Plasma Control: An Overview

Why a burning plasma must be actively steered every millisecond, and how a layered control system keeps it inside a narrow operating window.

Plasma Copilot: Breeder Disruption-Avoidance Advising

The copilot watches the twin's disruption precursors and margins, explains why risk is rising, and proposes avoidance moves — while fast mitigation stays in hardware.

Plasma Current Control

Plasma current control regulates the total toroidal current, the quantity that anchors confinement, stability, and the safety factor.

PLC and Safety PLC Security

Programmable logic controllers run the plant's control logic, and their security, especially for safety-rated controllers, is uniquely consequential.

PLC Deterministic Controls

Programmable logic controllers run the plant's slower deterministic sequencing and interlocks, complementing the FPGA fast loops with certified logic.

Plug-Coil Overstress Protection

At the design bore the burner plug coil is stressed 3-3.9x beyond feasibility; the protection loop treats coil stress as a first-class safety limit, not a design detail.

Plug-Stability Supervision

The burner's tandem-mirror end plugs must hold continuously; orchestration supervises plug field and stability and gates every corrective setpoint.

Pole Placement by State Feedback

State feedback u = -K x can move a controllable system's closed-loop poles to any chosen locations, setting its dynamics by design.

Polling vs Interrupt-Driven I/O

Software can wait for an event by repeatedly checking or by being interrupted; each has distinct latency, overhead, and determinism characteristics.

Pontryagin's Maximum Principle

Pontryagin's principle gives necessary conditions for optimal control through a Hamiltonian and an adjoint costate system.

POVMs

Positive operator-valued measures describe the most general quantum measurement, going beyond projective observables.

Predictive Maintenance

Turning telemetry into scheduled maintenance so faults are fixed on plan, not on failure - the strategic lever on availability.

Predictive Shadow Visualization

Drawing the twin's 50-100 ms lookahead as a labeled forecast beside the live state so operators see where the machine is going, with its uncertainty.

Preemption & Priority Inheritance

Priority inheritance stops a low-priority plan holding a shared resource from blocking a high-priority safety action.

Preference-Based RL for Control Policies

Human preference feedback shapes control-policy behavior where a scalar reward is hard to specify, but only in simulation and only behind the full validation and canary chain.

Production Model Monitoring

A model with authority is watched every cycle — inputs, outputs, uncertainty, latency, and agreement with physics — so degradation is caught before it becomes a fault.

Quantifying Precursor Lead Time

The value of a precursor detector is the lead time it buys; Kronos measures lead-time distributions and designs actuation around the time available.

Quantization and Pruning for the Edge

Models are shrunk to meet the L1 latency budget through quantization and pruning, with accuracy and calibration re-verified so compression never silently degrades safety.

Quantum Phase Estimation Worked Out

Estimate the eigenphase of a unitary using a counting register, controlled powers, and an inverse QFT.

Quench & Disruption Precursor Features

Sub-threshold signatures engineered from magnetics, strain, and profile telemetry give the anomaly ensembles a head start on quench and disruption.

Quench Detection

A quench is the loss of superconductivity in part of a coil; detecting the resistive voltage it produces fast enough is the core protection problem.

Quench Detection and Protection

The millisecond loop that catches a spreading normal zone in the superconducting coils and dumps stored energy safely.

Quench Detection Hardware

Above the passive failsafe, an FPGA estimator fuses co-wound voltage, thermometry, and REBCO strain to detect quenches earlier and localize them.

Quench Protection and Energy Dump

Once a quench is confirmed the magnet's stored energy must leave the coil fast enough to keep the hot spot below damaging temperature.

Quench Protection Reflex Chain

A superconducting magnet losing superconductivity must be detected and de-energized in milliseconds; the quench chain is the fastest shared reflex on both machines.

Quench-Abort Orchestration

A magnet quench is the highest-priority breeder event; orchestration coordinates a fast, safe, pre-authorized shutdown that preempts all else.

Radiated-Power Control

Radiated-power control regulates how much and where the plasma radiates, protecting surfaces without collapsing the core.

Ramp-Down Control

Ramp-down safely unwinds a discharge from flat-top to termination, avoiding the disruptions that a careless shutdown can trigger.

Ramp-Down Control

Bringing current and stored energy down on a controlled path - a phase as disruption-prone as ramp-up if handled carelessly.

Ramp-Up Control

Ramp-up brings a discharge from breakdown to the flat-top current while keeping the plasma stable and the current profile well behaved.

Ramp-Up Control

The early, fragile phase where current and shape are established while avoiding the instabilities that thrive at low current and density.

Random Seeds and Stochastic Reproducibility

Randomized computations reproduce only when their randomness is controlled; a recorded seed turns chance into a repeatable input.

Rate Limiting & Quotas for Actuation

Even valid commands are throttled to engineering slew limits and per-actuator quotas so no burst can drive hardware faster than it may move.

Ratio Control

Ratio control holds two flows or quantities in a fixed proportion by driving one to track a scaled version of the other.

Real-Time Analytics

Real-time analytics answers queries over data that is seconds old, combining fast ingestion, incremental computation, and low-latency serving.

Real-Time Anomaly Detection Across Subsystems

Watching many sensor streams at once to flag deviations from normal behavior fast enough to act on them.

Real-Time Compute Actuators

The bridge from digital command to physical effect is the actuator driver: deterministic RT-compute stages that turn setpoints into coil currents, beam power, and grid voltages.

Real-Time Computing

Real-time computing guarantees not just correct answers but answers delivered within a strict, predictable time bound.

Real-Time Computing for Plasma Control

Plasma control depends on hard real-time computing, where meeting a deadline every cycle matters more than raw average throughput.

Real-Time Computing for Twins

The control-relevant parts of a twin must produce answers within hard deadlines, which shapes their algorithms and hardware.

Real-Time Control & Safety

The sub-10µs control loop, synchronized gates, autonomous failsafe, and human oversight.

Real-Time Control Networks

Plasma and component control demand deterministic communication, so a real-time network moves sensor and command data on a fixed, guaranteed schedule.

Real-Time Decoding Latency

Decoders must return corrections fast enough to keep up with the syndrome stream, or the unprocessed backlog grows and computation stalls.

Real-Time Diagnostics for Control

The subset of plasma diagnostics fast and reliable enough to close control loops, and what each contributes.

Real-Time Inference for Control

Running a model fast and reliably enough to sit inside a plasma control loop.

Real-Time Linux vs FPGA

Real-time operating systems bound scheduling latency in software, but only fabric removes it; Kronos uses RT-Linux for supervision and FPGA for the fast loops.

Real-Time Operating Systems

An RTOS provides bounded, predictable scheduling and services so that timing guarantees, not just average performance, can be proven.

Real-Time Operator Dashboards

An operator dashboard turns a live stream of measurements into a compact, glanceable picture of machine state and margin to limits.

Real-Time Plasma Control

A fusion plasma changes on millisecond timescales, so control loops must sense, decide, and act faster than the instabilities they suppress.

Real-Time Plasma Flight Simulators

A plasma flight simulator runs a fast physics model in place of the real machine so controllers can be tested and tuned before a discharge.

Real-Time State Estimation

Real-time state estimation fuses many noisy diagnostics into one best picture of the plasma, fast enough for Kronos's control system to act within its latency budget.

Real-Time State Estimation with ML

Inferring the current plasma state from partial, noisy diagnostics fast enough to feed control.

REBCO Quench Detection Timing

REBCO conductors quench with a slow-propagating normal zone that is hard to see electrically; detection must be sensitive and fast without tripping on noise.

REBCO Strain and Quench Sensing

REBCO tape is strain-sensitive; L1 reads distributed strain gauges to catch conductor disturbances that can precede a thermal quench.

REBCO Strain-Gauge Anomaly Detection

High-field REBCO tape is strain-sensitive; Kronos monitors distributed strain gauges to catch mechanical precursors to conductor degradation and quench.

Receding Horizon and Real-Time Feasibility

MPC re-solves every cycle; Kronos chooses horizon length and solver so the plan is both far-sighted enough and fast enough for the control cadence.

Redundancy Architectures

Redundancy uses multiple channels so a single failure does not defeat a function; the architecture chosen trades availability against safe-fault detection.

Reflex and Supervisory Tier Separation

Intelligence proposes on a slow horizon; reflex disposes on a fast one. Keeping these tiers physically separate is what lets the safety case ignore the AI entirely.

Reinforcement Learning for Plasma Control

Reinforcement learning trains control policies against a simulator, offering a route to coordinate many actuators toward hard-to-specify goals.

Reinforcement Learning for Shape Control

Training control policies in simulation to steer plasma shape and position, and the honest limits of the approach.

ReLU and Variants

The rectified linear unit is the default hidden activation of deep learning: cheap, non-saturating, and easy to differentiate.

Repeated Syndrome Extraction in 3D

Because measurements themselves fault, syndromes are extracted over many rounds and decoded as a three-dimensional spacetime history.

Resiliency Verification and Drills

Proving the resiliency stack works by injecting faults in simulation and demanding a safe outcome every time - before hardware exists.

Reward Shaping for Plasma Control

Designing the reward signal so a learned controller pursues the physical goal and not a loophole.

RLHF for Operator Copilots

Operator copilots are tuned with reinforcement learning from human feedback so their suggestions match how expert Kronos operators actually reason — never to grant them control.

Robust Control

Robust control guarantees stability and performance despite bounded uncertainty in the plant model, designing for the worst case.

Role-Based Access Control

Granting permissions to roles rather than individuals, so access follows job function and is easy to review and revoke.

Runaway Electron Control

Runaway electrons accelerated during a quench can damage the wall; control aims to prevent their formation or safely dissipate the beam.

Runtime Assurance (Simplex)

A certified simple controller that provably takes over when the learned policy is unverified.

Safe Exploration in Learned Control

Keeping a learning or learned controller inside physically safe bounds on hardware where mistakes are costly.

Safe Reinforcement Learning

Constrained-RL control policies trained in the twin, deployed behind the clamp.

Safe Shutdown Sequences

The controlled procedures that bring a plasma to rest with minimal stress on the machine, whether planned or triggered by fault.

Safety Factor and q-Profile Control

Controlling the winding of the magnetic field, which governs stability, through the current profile.

Safety Integrity Levels

SILs grade how reliably a safety function must perform, turning a hazard's severity into a measurable target for the protective system's design.

Safety Interlocks and Instrumented Systems

Interlocks are simple, independent safety functions that act automatically when a hard limit is crossed, regardless of the control software.

Safety Interlocks and Machine Protection

The independent protection system that guards the machine regardless of what the control system is trying to do.

Safety vs Security Tradeoffs

Safety protects people from the system; security protects the system from people. Their measures sometimes pull in opposite directions.

Safety-Case Replay and Decision Evidence

Every trip, override, and gated action is recorded with enough fidelity to replay the event deterministically and prove the safety layers behaved as designed.

Safety-Critical Cyber-Physical Design

Cybersecurity and functional safety are co-designed so that no cyber event - however severe - can prevent the machine from reaching a safe state.

Safety-Envelope Checks

The envelope checker validates that a command keeps the machine inside a state-dependent safe region, not just under individual scalar limits.

Safety-Instrumented System Isolation

The safety-instrumented system is physically and logically independent of the control network, with a one-way status feed out and no command path in.

Safety-Instrumented Systems

A safety-instrumented system is an independent layer that detects dangerous conditions and forces the process to a safe state, separate from normal control.

Sawtooth Control

Sawteeth are periodic core relaxations; control tunes their period so they flush impurities without seeding larger instabilities.

Sawtooth Oscillations and Reconnection

Periodic internal crashes that flatten the core when the central safety factor drops below one.

Scaling Challenges

Growing from hundreds to the millions of qubits fault tolerance needs runs into wiring, heat, control, calibration, and error-correction bottlenecks at once.

Scenario and Trajectory Control

Designing and executing the time-varying reference trajectories that carry a plasma safely from breakdown to controlled termination.

Scheduling Optimization for Maintenance

Planning maintenance activities to keep a plant available while respecting resource, access, and safety constraints.

Self-Triggered Control

Self-triggered control predicts the next update time at the current update, eliminating the continuous monitoring that event-triggered control requires.

Self-Tuning Regulators

A self-tuning regulator estimates plant parameters online and continually redesigns the controller as if the estimates were exact.

Sensitivity Analysis

Finding which inputs a result depends on most, to focus measurement, control, and design effort where it pays.

Sensitivity Analysis in Code Workflows

Sensitivity analysis ranks which inputs most influence an output, focusing effort on the parameters that actually control a prediction.

Separation of Duties and Two-Person Control

Consequential actions require two people in distinct roles, so no single credential holder can move the machine to a high-consequence state or bypass safety alone.

Shadow Deployment of Controllers

A shadow controller runs on live machine data and computes what it would command, but its outputs go nowhere near an actuator — pure observation before authority.

Shape Control: Negative Triangularity

Maintaining the breeder's delta -0.30 boundary is a continuous feedback task; L1 tracks shape moments and corrects the plasma-facing profile in real time.

Simpson's Rule

Simpson's rule fits parabolas through triples of points, achieving fourth-order accuracy that integrates cubics exactly.

Sliding-Mode Control

Sliding-mode control forces the state onto a stable surface and holds it there, giving strong robustness at the cost of chattering.

Sliding-Mode Control in Detail

Sliding-mode control forces the state onto a designed surface and holds it there, giving strong robustness to matched uncertainty at the cost of chattering.

Smith Predictor

The Smith predictor compensates for process dead time by using a model to predict the delayed output and control against the prediction.

Stability Margins and Control Headroom

A loop that only just holds is a loop about to fail; Kronos designs gain and phase margin plus actuator headroom so faults have somewhere to be absorbed.

Stability-Problem Map Across Both Machines

The same variational stability question specializes to different operators on the breeder and the burner; this map pairs each mode with its equation and its AI treatment.

State-Space Control

State-space methods describe a system by its internal state vector, enabling systematic control of coupled, multivariable dynamics beyond single-loop PID.

Stochastic Model Predictive Control

Stochastic MPC handles random disturbances with chance constraints, enforcing limits with a specified probability rather than for the worst case.

Stream Processing

Stream processing computes over unbounded data as it arrives, using windows, watermarks, and stateful operators to produce continuous results.

Sub-10 Microsecond Latency Budget

The fastest protection loops must close under 10 microseconds; this page decomposes that budget stage by stage and shows the timing margin.

Sub-Microsecond Sampling

The acquisition chain digitizes every analog channel below the microsecond, fast enough to resolve the transients that precede disruptions and plug collapse.

Sub-Threshold Alarming and False-Alarm Control

Detecting precursors below protection thresholds only helps if the alarm rate is low enough to act on; Kronos tunes thresholds against a cost of false vs missed alarms.

Superconducting Magnet Quench Codes

Quench codes model the transition of a superconducting magnet to the normal state, predicting temperature, voltage, and the protection a coil needs.

Supervisory Control and State Machines

The supervisor sequences discharge phases, enables and disables controllers, and holds the logic that ties fast loops into one discharge.

Surrogate Acceleration of the Twin

Full multi-physics solves are too slow for real-time control, so Kronos distills them into fast surrogates that preserve the physics that matters.

Synchronized Actuation Gates

Commands do not reach actuators the instant they are computed; they pass a synchronized gate that admits them only in a valid window and only when all interlocks agree.

Synchronized Actuation Gates

Multiple actuators must fire on a common time base; L1 uses synchronized gates so coordinated commands take effect at the same deterministic instant.

Taylor-Series (Truncated Dyson) Simulation

Building the time-evolution operator by truncating its power series and implementing the sum as a linear combination of unitaries.

Tearing-Mode and NTM Control

Detecting and suppressing magnetic islands that degrade confinement and can lock into disruptions.

The 50-100 ms Predictive Shadow

KRONOS-CTRL runs ahead of the real plant, holding a 50-100 ms forecast so controllers act on where the machine is going, not only where it is.

The 8-Layer Control Architecture

A layered control stack that spans microsecond hardware reflexes to a predictive digital twin and human oversight, each layer with its own latency budget.

The AI-Native Fusion Plant

An AI-native plant treats computation as a core subsystem, not an add-on: design, control, and operations share one model of the machine.

The Autonomous Hardware Failsafe

A self-contained hardware chain detects a magnet delta-T precursor and dumps the quench with zero latency and zero dependence on any AI or software.

The Bravyi-Kitaev Transformation

A fermion-to-qubit encoding that stores occupation and parity information in a tree structure, cutting operator locality to logarithmic scale.

The Cold-Electronics Stack

The cold-electronics stack distributes signal generation, amplification, and control across temperature stages to match each function to the cooling available.

The Control-Room Display

A control-room display is a shared, stable, high-reliability view designed so a team can maintain situational awareness under pressure.

The Current Diffusion Equation

The resistive-diffusion equation that evolves the poloidal flux and hence the safety-factor profile.

The Design Philosophy

Five principles govern the architecture: safety is physical, intelligence is bounded, data is the asset, layers are contracts, and the twin is the source of truth.

The Dispatch Command API: A Safe Write Model

The write plane accepts bounded, idempotent commands that are validated, envelope-clamped, and staged into the L1 control plane rather than executed blindly.

The Disruption-Free Operation Strategy

Reliable operation is not one trick but a layered strategy combining prediction, avoidance, control, and safe termination.

The Eastin-Knill Theorem

No quantum code can implement a universal gate set transversally, forcing every fault-tolerant scheme to use a non-transversal technique for at least one gate.

The Eight-Layer Stack

L0 Foundation to L7 Ecosystem: a strict layered separation that isolates microsecond safety from petabyte-scale learning.

The Finite Volume Method

Finite volumes integrate conservation laws over control cells so that fluxes between neighbors cancel exactly, enforcing conservation by construction.

The Fokker-Planck Collision Operator

The velocity-space diffusion and drag operator describing cumulative small-angle Coulomb collisions.

The Fokker-Planck Equation

The kinetic equation that adds small-angle Coulomb collisions as a drift-and-diffusion operator in velocity space.

The Fusion Triple Product

The single figure of merit n T tau_E that compresses the ignition requirement into one number.

The Greenwald Limit in Control

How the empirical density limit constrains real-time density control and why staying below it is a scenario design requirement.

The Kronecker Product

A block-structured product of two matrices that builds large operators from smaller ones.

The Kronos Layered Control Stack in Operation

The Kronos control stack layers fast stabilization, feedback regulation, supervision, and protection into one coordinated system.

The Kronos Quantum Roadmap

A staged, honest plan: benchmark now, invest in fault-tolerant materials simulation later, and treat the He-3 link as the nearest-term reality.

The Kruskal-Shafranov Limit

The current-driven external kink threshold requiring the edge safety factor to exceed unity.

The L0 Foundation Layer

L0 is the offline, high-compute substrate that trains, simulates, and re-grounds everything the real-time layers do for both Kronos machines.

The L1 Deterministic Reflex Loop

L1 is the hard real-time reflex tier: a fixed-latency sense-decide-actuate loop whose worst-case timing is proven, not measured after the fact.

The L1 to L2/L3 Boundary

L1 streams validated telemetry up and receives advisory targets down, but its safety and timing guarantees never depend on the layers above it.

The Latency Gradient

From microseconds at the edge to hours at the foundation, each layer operates at the timescale its responsibility demands.

The Latency Gradient Across Layers

From sub-10-microsecond actuation at L1 to multi-hour Monte Carlo at L0, the stack spans nine orders of magnitude in time — deliberately.

The Low-Latency Feature Store

A feature store serves engineered features to control, the twin, and the copilots at low latency, guaranteeing the same values online and offline.

The Lundquist Number

The ratio of resistive diffusion time to Alfven transit time, controlling the rate of magnetic reconnection.

The ML-Independent Hardware Failsafe

The last line of defense contains no machine learning and no general-purpose software; it trips to a defined safe state through logic simple enough to certify by inspection.

The Overhead of Fault Tolerance

Fault tolerance multiplies the number of physical qubits and operations needed, and estimating this overhead is central to planning real machines.

The Plant State API: A Governed Read Model

A high-fan-out read plane publishes a coherent, versioned snapshot of plant state drawn from the digital twin, never from raw control internals.

The Proximal Operator

The proximal operator generalizes projection: it finds the point that balances staying near a target against reducing a possibly nonsmooth function.

The Pulse Schedule and Waveform Control

The pulse schedule is the time-programmed plan of references and actuator waveforms that defines a discharge before it begins.

The Real-Time vs Offline Boundary

The architecture's central dividing line: hard real-time below, latency-tolerant learning above, with telemetry crossing up and validated models crossing down.

The Rendering Pipeline

Turning geometry into pixels follows a fixed sequence of stages; knowing them is the basis for every real-time 3D visualization.

The Ry Gate

The Ry(theta) gate rotates with real amplitudes - the best-behaved trainable gate, and Kronos's default for encoding data and parameters in fusion circuits.

The S.M.A.R.T. Generator Plant Interface

The boundary where the software stack meets steel: every layer terminates in a named subsystem, sensor, or actuator on the real machine.

The Safety Factor Formula

The number of toroidal transits a field line makes per poloidal transit, the master parameter of tokamak stability.

The Safety Factor q

The number of toroidal transits a field line makes per poloidal transit, central to tokamak stability.

The Safety Hierarchy and AI

Safety is layered: deterministic hardware at the floor, bounded control above it, and AI advisory at the top — the higher the intelligence, the less it can harm.

The Sensor-to-Actuator Pipeline

From feedthrough to physical gate, L1 is one deterministic pipeline whose stages each carry a bounded latency that composes into a certified whole.

The Separation Principle

For linear systems, the optimal controller and optimal estimator can be designed independently and combined without loss of optimality.

The Shadow Latency Budget

For the predictive shadow to lead the plant, every stage from telemetry to twin update must fit within a strict latency budget.

The Stabilizer Formalism

Describing states by the Pauli operators that fix them yields a compact language for error correction and efficient simulation.

The Stack and the DEC Train

How the architecture controls the burner's multi-modal direct-energy-conversion train — TWDEC, ultra-high-field MHD, and thermionic stages.

The Stepped L7-to-L0 Hierarchy

Command authority descends in steps from strategy at L7 to microsecond actuation at L1, tightening latency and narrowing scope at each step.

The Sub-10-Microsecond Command Boundary

Every safety-critical actuation on both machines must complete inside a 10-microsecond deterministic window, from validated command to physical gate.

The T Gate

The T gate is the expensive non-Clifford gate whose count Kronos tracks as the real price of a fault-tolerant fusion-chemistry calculation.

The Time-Evolution Operator

How the unitary e^(-iHt) propagates quantum states, and why its structure sets the shape of every simulation algorithm.

The Toffoli Gate

The Toffoli gate is a controlled-controlled-NOT that makes classical logic reversible and is a key primitive in quantum arithmetic.

Theming and Shift-Aware Lighting

Displays that stay legible and low-fatigue as control-room lighting changes across day and night shifts, without altering the meaning of any color.

Thermal Anchoring and Wiring Heat Loads

Every wire entering a cryostat carries heat inward; controlling that load through anchoring, attenuation, and material choice is central to reaching base temperature.

Threat Model: Actuator Manipulation

Even with valid-looking commands, actuator behavior is bounded by rate limits, interlocks, and an independent shutdown path so manipulation cannot exceed a safe envelope.

Threat Model: Attacking the Plasma-Control Loop

An attacker who reaches the fast control loop would try to drive the plasma off its operating point; layered identity, attestation, and an independent safety path deny that.

Time Synchronization

Distributed real-time systems need a shared, precise clock so events can be ordered, timestamped, and coordinated across independent nodes.

Timing Budgets and Jitter

Determinism is defined by the spread of latency, not its average; L1 engineers jitter down to nanoseconds so worst-case equals typical-case.

Training a Tiny Disruption Classifier

Build a small logistic classifier that flags impending plasma disruptions from a few diagnostic features - a scaled-down version of a real fusion control task.

Transversal Gates

A transversal gate acts independently on corresponding qubits of code blocks, making it automatically fault-tolerant.

Triple-Modular Redundancy and Voting

Critical L1 channels are triplicated and voted so a single fault is outvoted, giving fail-operational behavior without a single point of failure.

Tritium Accountancy & Permeation

Real-time, safety-critical tritium inventory and barrier permeation.

Trust and Override: Keeping the Human in Command

How the interface lets an operator accept, question, or overrule the AI — with the context to do so well and a record of why.

Tube Model Predictive Control

Tube MPC keeps the true state inside a bounded tube around a nominal trajectory by combining a nominal optimizer with an ancillary error-rejecting feedback.

Tuning a PID Control Loop

Drive a process to a setpoint with proportional, integral, and derivative terms, and understand what each knob does.

Twin Latency and Timing

End-to-end latency, from sensor to corrected estimate to action, sets what a twin can control and must be budgeted deliberately.

Twin-in-the-Loop Control

Twin-in-the-loop control runs Kronos's digital twin alongside the real machine, so the controller can test an action against the model before committing it - and catch drift when t

Twin-in-the-Loop Control

Placing the twin inside the control loop gives the controller a live, corrected model to plan against, not a fixed design model.

Two-Phase Action Commit

The rare actions that must span two coupled actuators atomically use a prepare-then-commit protocol with a safe abort on any failure.

Type I and Type II Errors

Every hypothesis test can err two ways: a false alarm or a missed detection, and reducing one tends to raise the other.

Uncertainty Propagation in Fusion Design

Fusion performance predictions inherit uncertainty from physics inputs and models; propagating it turns single figures into honest, conditioned ranges.

Uncertainty Quantification

Attaching honest error bars to every Kronos prediction by propagating input, data, and model uncertainty through the workloads.

Uncertainty Sets

The uncertainty set is the modeling choice at the heart of robust optimization; its shape controls both conservatism and computational tractability.

Uncertainty-Aware ML Control

Control policies that quantify their own uncertainty can defer to safe fallbacks when they encounter conditions outside their training experience.

Vacuum Pumping Control

Pumping control regulates the removal of exhaust gas during a pulse, setting particle throughput while protecting each pump's operating window.

Vacuum System Control

A fusion device needs a very high vacuum before and during operation, maintained by staged pumps under continuous control and interlocking.

Verification and Validation of Control

Establishing that a control system does what it should before it is trusted with a machine - and keeping that trust over time.

Verification and Validation of Control Software

Control software must be shown correct before it commands a machine; verification checks the code, validation checks it against reality.

Version Control

Version control records every change to code and data so history is auditable, mistakes are reversible, and teams can collaborate safely.

Version Control for Science

Tracking every change to code and inputs so any result can be traced to the exact state that produced it.

Vertical Position Control

Actively stabilizing the vertical position of an elongated plasma, which is intrinsically unstable and must be corrected faster than it grows.

Vertical Stability Control

An elongated plasma is vertically unstable on millisecond timescales; L1 runs a fast feedback loop on the breeder to arrest vertical displacement before it grows.

Visualizing Uncertainty So Operators Can Judge It

The AI's confidence is never hidden behind a single number: distributions, bands, and hatching let operators see how much to trust each estimate on both machines.

Voting and Redundancy Architecture

Critical safety signals are triplicated and voted so that a single failed channel is outvoted and flagged, not obeyed.

VOx Quench-Bypass Dump

When the precursor trips, a metal-oxide switching element commutates coil current into an external dump, removing stored magnetic energy from the winding.

Warmup and Cosine Decay

The warmup-then-cosine schedule ramps the learning rate up briefly, then lowers it along a cosine curve to a small floor, a widely used default.

Watchdog Timers and Heartbeats

Every L1 controller proves it is alive by servicing a watchdog; a missed heartbeat forces the guarded actuator into its safe state.

What 'AI-Native' Means for a Fusion Plant

AI-native means the intelligence is not a bolt-on analytics layer but the control fabric itself — designed in from the plant's first block diagram.

Why Eight Layers

Eight was chosen so that each layer holds a single latency and safety class — fine enough to isolate microsecond safety, coarse enough to reason about.

Why Offline Compute Is Separated from Real-Time

The architectural decision to keep heavy, non-deterministic foundation compute strictly apart from the microsecond control plane.

XOR in Arithmetic and Logic

The exclusive-OR gate is the workhorse of digital arithmetic, comparison, parity, and controllable inversion.

Youla Parametrization

The Youla parametrization describes every stabilizing controller for a plant with a single free stable transfer function, making closed-loop maps affine.