The Multi-Modal DEC Train
No single converter captures a broad, two-species particle spectrum well, so the burner stacks TWDEC, MHD, and thermionic stages in series.
One spectrum, several converters
The charged output of a D-3He plasma is broad in energy and mixed in species. Any single conversion mechanism does one part of that job well and the rest poorly. The design answer is a train: put each converter where it is strongest, and let each stage hand its leftover energy to the next. This is the same logic as a combined-cycle plant, but built from non-thermal converters.
Roles in the train
- TWDEC — traveling-wave direct energy conversion, tuned to the fast, high-energy protons by decelerating velocity-sorted bunches in a radio-frequency structure.
- Ultra-high-field MHD — converts the ordered, expanding plasma flow directly into current as it crosses a strong magnetic field.
- Thermionic — mops up energy that lands as heat on hot collector surfaces by emitting electrons across a vacuum gap.
- Radiation recovery — bremsstrahlung and synchrotron photons are captured on cooled walls and, where useful, converted.
Why staging beats one big converter
A single electrostatic collector sized for 14.7 MeV protons wastes the 3.6 MeV helium-4 and cannot cope with the spread. Staging lets each converter operate near its own sweet spot and pass the remainder along, so the system efficiency is higher than any single stage. The cost is complexity: multiple high-voltage structures, careful handoff geometry, and coordinated control, all of which are the subject of the pages that follow.
The train is a design-and-simulation study today. Component physics is well understood individually; the burner program's task through the ~2032 test unit is to demonstrate them working together on a real plasma.