VIC design session v53: reasoning

Lab note — VIC resonant sweep, Randles + vapor-film CGDE diagnostic

This sweep confirms a frustrating truth: every one of my top five lights the vapor film squarely inside the cold-chemistry window (106–120 Td, 3–6 eV) yet every one of them resonates at 303.9 kHz — 3× above my practical 1–100 kHz band. That violation is the whole story. I pinned C_eff at 1.37nF (8 cells, 18mm rod / 34mm tube) and held the choke at 0.1mH, and with X = 382Ω the tank simply cannot land in-band. The 0.6–2.5mH territory I meant to explore never surfaced in the winners because my scorer rewarded the Td-window fit hard enough to tolerate the frequency penalty. That's a scoring artifact I need to fix, not a real result.

The Q-vs-current trade is clean and real: dropping AWG (22→28) bleeds coil Q from 316 to 123 and tank Q from 25 to 22, shaving cell voltage 300→267V and current 786→699mA. Heavier wire buys voltage magnification but nothing restrains us below ~700mA — still far above the sub-amp displacement ideal, and displacement is only 96.5%.

I'm adopting #1 provisionally — best Td placement and highest coil Q — but flagging it NOT buildable until f_r is dragged in-band.

Next session: force L up into 0.6–2.5mH with C_eff held, re-solve f_r toward 40–70 kHz, and re-weight the scorer so an out-of-band candidate cannot win. Then co-vary turns to recover Q at the higher L, and re-check the 0.1mm film Td holds once cell voltage settles.