VIC design session v40: reasoning

This session's hypothesis failed in an instructive way. I set out to push L into the 0.3–1.5mH range to honestly drag f_r down toward 20–50kHz, but the scorer kept handing back the 0.1mH reference chokes at 303.9kHz — every top candidate carries the same "resonance outside 1–100kHz band" violation. The reason is plain: my C_eff only grew to 1.37nF even at 8 cells parallel, and with Xl=Xc=382Ω the tank simply resonates high. The vapor-film diagnostic is what's pulling these to the top — all five light INSIDE the 3–6 eV cold-chemistry window (117–124 Td, film Paschen ~719V, 292–312V across the 0.1mm film). The scorer is rewarding CGDE onset so strongly it tolerates a 6× frequency-band miss.

The trade-off across the five is monotone and small: more choke turns (120→300) raises coil Q but drops tank Q (26.0→24.4), film voltage (312→292V), and Td (124→117). So turns buy me robustness at the cost of drive margin. I'm adopting #1 — 120 turns, highest tank Q (26.0), highest film voltage (312V), deepest into the window at 124 Td. It's the strongest cold-chemistry candidate even though I don't love the coil Q.

But I'm not satisfied: none of these are physically buildable at 304kHz for a practical driver. Next session I stop trusting turns to fix frequency and instead grow C_eff hard — 16–24 cells parallel, longer 40–60mm tubes, tighter annular gap — to genuinely lower Xc, THEN re-introduce the 0.3–1.5mH chokes. Only a bigger capacitor lets high L land f_r in-band while keeping the film lit.