VIC design session v67: reasoning

This sweep taught me something uncomfortable: at 0.1mH the whole top-five collapses onto a single resonant point, f_r = 303.9kHz, and every one of them violates my practical 1-100kHz band. The 0.1mH choke is simply too small to pull f_r down against a 1.37nF cell — I confirmed the crossing to sub-100kHz needs the 0.8-1.6mH heavy-gauge band I flagged, not this fine grid. So I'm reading these candidates as a Q/current study, not as buildable frequencies.

The trade-off is clean and instructive. Holding L and C fixed, the only lever left is coil resistance, and it sets tank Q directly. AWG18 at 220 turns gives coil Q 322 → tank Q 25.1 → 301V across the film and 120 Td — deepest into my 80-250 Td / 3-6 eV cold-chemistry window. Drop to AWG21 and coil Q falls to 80, cell voltage to 244V, 97 Td — still lit, but with less margin and, notably, less current restriction lost for nothing. Higher Q buys both voltage AND stays inside the window here; there's no penalty trade yet because breakdown margin is ×1000+ and displacement current is pinned at 96.5%.

I'm adopting #1 (AWG18, 220 turns) — highest score, best film energy, tightest current at 787mA. But I will NOT build it at 304kHz. Next session: re-run this exact cell and gauge at 0.8, 1.0, 1.2, 1.6mH to drag f_r under 100kHz, watch whether coil Q survives the added wire, and confirm the 120 Td window holds once I'm in-band. That's the real prize.