Physical Interface Taxonomy

Every place the Kronos control stack touches metal, gas, or plasma is a typed interface with an owning layer, a latency budget, and a calibration record.

What a physical interface is

A physical interface is the boundary where a software layer of the AI-native stack reads a sensor or drives an actuator on real hardware. On the breeder (Hyperion, a D–T spherical tokamak) and the burner (Aegis / MetroVolt, a D–³He tandem-mirror generator) these interfaces span magnets, fueling, the fuel cycle, the vessel, the divertor / first wall, the burner direct-energy-conversion (DEC) train, and 60+ diagnostic ports.

Each interface is documented with the same five attributes so that any layer — and any AI agent reading this repo — can reason about it: signal set, owning layer, direction (sense / actuate / bidirectional), latency class, and calibration source.

The interface classes

• Magnet interfaces: REBCO coil supplies, quench detection, strain and cryogenic thermometry.
• Fueling interfaces: ice-piston and pellet injectors, gas-puff servo valves, neutral-beam injection.
• Fuel-cycle interfaces: tritium plant, helium-3 handling, deuterium metering, lithium blanket, accountancy.
• Structural interfaces: vessel structural-health monitoring, first-wall thermal, divertor/expander.
• Power-extraction interfaces: burner DEC collector grid and grid-voltage modulation.
• Diagnostic interfaces: magnetics, Thomson scattering, interferometry, neutron cameras across 60+ ports.

Ownership rule

Latency decides ownership. Anything that can move energy or open a fault inside µs–ms is owned by the hard real-time L1 control plane; slower supervisory, campaign, and accountancy interfaces are owned by L3/L4/L7. The hardware-abstraction contracts make the boundary explicit and testable. This taxonomy is a design-and-simulation map: the machines are not yet built, and no hardware net-gain is claimed before FOAK first tritium (~2030).