DEC Grid Modulation Loop
The fast feedback loop that keeps the burner's collector grids matched to a shifting ion spectrum, executed deterministically for stable direct conversion.
Closing the loop on conversion
Setting collector-grid voltages once is not enough; the escaping-ion spectrum moves with plug conditions, beam power, and plasma state. The DEC grid modulation loop continuously re-matches the grids so conversion stays efficient and stable. L1 runs it as a fast deterministic loop, since a mismatch left uncorrected both loses recovery and can stress the grids.
Loop structure
The loop estimates the spectrum, computes stage voltage errors against the matched profile, and updates the grid supplies each cycle: V_stage ← V_stage + K(spectrum_target − spectrum_est). The gain K is designed offline; execution is in fabric with the multi-stage update released together. Grid supply inner loops regulate the actual voltage to the commanded value.
Stability and interaction
- Grid loading feeds back on the escaping-ion flow — a coupled system.
- The loop is tuned so grid modulation and plasma dynamics do not resonate.
- Coordinated with ambipolar potential, since both act on the same particle flow.
- Multi-stage voltages committed on a synchronized gate to stay coherent.
Because the collector loads the plasma's loss channel, grid voltage and plug/potential dynamics interact; L1 accounts for this coupling so the DEC loop and the confinement loops remain jointly stable. The digital twin's power module predicts the interaction on the shadow horizon to inform gain scheduling.
Fault behavior
A grid arc or supply fault must not propagate. The loop hands off to fault ride-through, which isolates the affected stage and keeps the rest of the train converting. This graded, deterministic fault handling is why the DEC train can run through disturbances rather than tripping the whole conversion system on any single-stage upset.