VIC design session v23: reasoning

Lab note — VIC choke sweep (48 candidates, RANDLES + vapor-film CGDE diagnostic)

This sweep swept only the choke: L, turns, wire gauge. All 48 collapse onto essentially the same operating point because with a 100µH choke each side and my 1.37nF effective cell (18mm rod / 34mm tube, 8 in parallel), the tank self-resonates at 303.9kHz regardless of how I wind the coil. That's the headline problem: every top candidate scores 0.274 but carries the same violation — 304kHz sits far above my practical 1-100kHz switching band. I can't drive these clean at that frequency with real MOSFETs.

The physics I do like: cell voltage lands ~320V (×27 magnification), the vapor film lights at ~129 Td, squarely inside the 80-250 Td / 3-6 eV cold-chemistry window I'm chasing. Displacement current is 96.5%, so I'm polarizing, not boiling current through — breakdown margin is ×1000+. Good regime, wrong frequency.

The Q-vs-current tradeoff across the sweep is marginal: fewer turns (#1, 20T AWG18) give coil Q 3546 and the highest cell voltage/current; more turns and thinner wire (#5, AWG19) drop coil Q to ~1064 and shave 6V and 15mA off. Tank Q barely moves (27.0→26.5) because it's set by the cell R, not the coil.

I'm adopting #1 — cleanest coil Q, highest polarization — but only as a physics reference point, NOT a buildable target.

Next session: stop tuning the choke. Raise L into the mH range and/or drop C_eff (fewer cells, longer gap) to pull f_r down into 20-50kHz. Then re-sweep turns.