VIC design session v94: reasoning

Lab note — VIC resonant sweep, Randles + vapor-film scoring.

The intent this session was to force f_r up into the untested 32–50 kHz band with 3.7–9 mH high-turn chokes. The honest result: I didn't get there. Every surviving top candidate parks at 12.91 kHz with 3.7 mH chokes. The reason is the cell — 8 tubes in parallel drove C_eff to 20.5 nF, and 1/(2π√LC) with 3.7 mH lands squarely at 13 kHz. To reach 40 kHz I'd need either ~10× less capacitance (fewer tubes/parallel cells) or far smaller chokes, which the sweep bounds didn't allow to co-exist with the turn count. So the "higher frequency" question is unanswered; the optimizer simply refused to trade band for score.

The trade-off it exposed is blunt: tank Q is stuck at 1.2 even though coil Q is 66.7. The choke is fine; the water branch (509 Ω series R, 53.8% displacement current) is dumping the energy. No high-frequency magnification is possible until that resistive loss drops. Higher voltage helps the physics that matters more — candidate #5 pushes 400 V drive → 463 V cell → 185 Td, deepest into the 3–6 eV cold-chemistry window, at only 23 mA average.

I'm adopting #5. Same score, but it lights the vapor film hardest inside the CGDE window at low duty, which is the yield lever, not Q.

Next session: cut parallel cell count to 1–2 to shrink C, pair with 8–9 mH chokes to legitimately hit 40 kHz, and sweep purer water (0.5–1 ppm) to raise series R breakdown margin and cut displacement losses.