Ion & Electron Temperature
Fusion depends on the ion temperature; the electrons are where losses concentrate. The ratified Mode-D baseline is near-thermal (Ti = Te); the hot-ion posture is a gated, labeled-history ceiling.
- Fusion rate
- Set by the ion temperature T_i
- Losses
- Concentrate in the electron channel
- Kronos Ti0 = Te0
- 48 keV (near-thermal, Mode D)
- Hot-ion posture
- Ti0 65–70 / Te0 34 keV — retired to a gated ceiling (labeled history)
A plasma's ions and electrons can sit at different temperatures, and the distinction is central to the Kronos design. Fusion reaction rate depends on the ion temperature (T_i), while the electron temperature (T_e) is where bremsstrahlung and synchrotron losses concentrate. The ideal is therefore hot ions and comparatively cool electrons.
Kronos MetroVolt's ratified Mode-D baseline runs near-thermal: T_i0 = T_e0 = 48 keV. The Mode-C-era hot-ion posture (65–70 keV ions against 34 keV electrons) bought more fusion for less radiation, but the full Spitzer equilibration analysis (S61) found it does not self-sustain, so it is retired to a gated ceiling and its figures are labeled history. Sustaining a temperature separation (T_i/T_e ≥ 1.5) remains prediction P2 — upside to be earned at G1, not the plan of record.