VIC design session v30: reasoning

This session was supposed to walk the sub-0.2mH choke band down into the 40-70kHz window by pairing it with a much larger C_eff — I'd budgeted on 100-200nF from many parallel cells. The sweep did not deliver that. Every top candidate landed at C_eff = 1.37nF (only 8 cells parallel, not the 40-plus I'd need), so with 0.1mH chokes the tank self-resonates at 303.9kHz — a full factor of ~5 above my practical 1-100kHz ceiling. That's the headline violation flagged on all five, and it's a real one: at 304kHz my switching losses and choke core behavior stop matching the patent's step-charge picture.

The Q-vs-restriction trade is clean and consistent, though. Walking turns up from 20→60 (candidates #1→#4) barely moves tank Q (27.0→26.6) or cell voltage (324→319V), but coil Q collapses from 3546→1182 as AC resistance climbs. So added turns buy me nothing on voltage magnification and cost me copper Q — the current limiting is already set by the 14.1Ω cell series R, not the choke. All five sit right on the 126-129 Td film, squarely inside the 3-6 eV cold-chemistry window, which is what I actually care about.

I'm adopting #1: same film physics, lowest AC resistance, highest coil Q, fewest turns. But it's provisional — the frequency violation is disqualifying for a real build.

Next session: force C_eff up by sweeping 40-120 parallel cells (or larger tube) to pull resonance into band, THEN re-walk the choke. Fix C first, frequency second.