Bremsstrahlung & Synchrotron Recovery

A hot plasma radiates energy as X-rays and microwaves; capturing that radiation on cooled surfaces recovers part of it before it is lost.

Radiation is a third energy channel

Besides charged particles and neutrons, a fusion plasma loses energy as radiation. Electrons decelerating in the field of ions emit bremsstrahlung (broadband X-rays), and electrons gyrating in the strong magnetic field emit synchrotron/cyclotron radiation (microwaves). At the burner's high fields and temperatures both are significant, and neither is charged, so DEC cannot act on them directly.

How it is recovered

• Synchrotron microwaves are largely reflected by metal walls and can be partly reabsorbed by the plasma, reducing the net loss.
• Bremsstrahlung X-rays are absorbed in the first wall and shielding, depositing heat that joins the thermal share.
• That absorbed heat can feed the thermionic bottoming stage or the cooling loop, so it is not entirely wasted.

Why it matters for the budget

Radiation is a real loss channel that lowers the fraction of energy available as charged particles. The design keeps it in check by choosing plasma conditions and wall materials that minimize net radiation and by reflecting synchrotron power back into the plasma. What is not returned is captured as heat and handled with the neutron thermal share — again, on cooled surfaces rather than in a steam cycle.

Honest note

Radiation recovery is partial by nature: X-rays absorbed in structure become heat of modest quality, and only a fraction can be reconverted. Counting it honestly means treating radiation as mostly a loss to be minimized and partly a heat stream to be skimmed — not as a major direct-conversion channel. It is included here so the energy budget is complete.