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.
Converting output directly
On the burner, the direct-energy-conversion (DEC) train is where the plasma's charged-particle output becomes usable energy without a conventional thermal cycle for that fraction. It is a multi-modal train, and the architecture controls it as an orange reactor/thermal path with its own diagnostics and actuation.
The stages
- TWDEC — traveling-wave direct energy conversion, decelerating fast ions and recovering their energy.
- Ultra-high-field MHD — a magnetohydrodynamic conversion stage.
- Thermionics — direct thermal-to-electric conversion of the residual heat.
The control problem
DEC control is coupled to plasma control: the flux and energy spectrum entering the train depend on the end-plug density and the ambipolar potential upstream. The MPC agent must therefore steer the escaping charged particles into the train's acceptance window while the plasma loop holds the plug — a single coordinated objective across L3.
Why it is a shared-stack module, not a new stack
The DEC train is unique to the burner, but it does not need a new architecture. It is a set of L2 diagnostics, an L3 twin sub-model, and L1 actuation — the same layers, pointed at conversion instead of confinement. This is the one-architecture principle applied to the output end of the machine.
Multi-modal by design
The three stages are complementary because the escaping population is not monoenergetic. TWDEC recovers the fast directed ions most efficiently; the ultra-high-field MHD stage handles the bulk flow; thermionics captures residual heat that the first two stages leave behind. The twin models the energy spectrum entering the train so the MPC agent can bias operation toward whichever stage matches the current output — a conversion-side optimization that mirrors the confinement-side optimization on the breeder.
DEC control sits inside the burner control problems and is executed within the command boundary.