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.

One train, several modes

The burner's energy leaves in several forms — directed charged-particle flow, bulk plasma flow, and thermalized heat — so a single conversion method cannot capture all of it. Kronos uses a multi-modal DEC train: traveling-wave direct energy conversion (TWDEC), ultra-high-field MHD conversion, and thermionics, each matched to an energy channel. L1 coordinates the modes so they cooperate rather than compete for the same flow.

The modes

• TWDEC: decelerates a bunched, directed ion beam by phased RF fields, recovering directed kinetic energy.
• Ultra-high-field MHD: extracts energy from conducting plasma flow crossing a strong field.
• Thermionics / grids: capture thermalized and lower-energy fractions.
• Electrostatic collector grids: the graded-voltage stage detailed elsewhere.

Each mode has its own actuators and control loop — RF phase and amplitude for TWDEC, field and load for MHD, emitter/collector conditions for thermionics — and L1 runs them on a common clock so their handling of a shared particle and energy flow is coordinated, not conflicting.

Coordination logic

The train is a sequence: earlier stages take the energy bands they convert best and pass the remainder downstream. L1 schedules stage setpoints so the escaping-ion spectrum is progressively harvested, using the gate mechanism to keep multi-stage updates coherent. The twin's power module predicts the end-to-end recovery to guide the coordination.

Determinism and neutrons

D-3He is low-neutron (neutron fraction 5.44%), not aneutronic, so a small neutron-carried energy fraction is handled thermally rather than by direct conversion. L1 accounts for this split in coordinating the modes. Every mode's fast loop is deterministic, and every mode participates in fault ride-through so the train degrades gracefully.