VIC design session v45: reasoning

Lab note — VIC resonant sweep, intermediate-L hunt

The intent this session was to walk L up from the 0.1mH high-Q champion toward the 2.5mH drivable floor and catch the exact inductance where f_r drops under 100kHz while a ~120 Td film still lights in the CGDE cold-chemistry window. That's not what the optimizer handed back. Every one of my top five clung to the 0.1mH choke and parked at f_r = 303.9kHz — all still carrying the 1-100kHz band violation. The scorer is telling me plainly that CGDE window occupancy (114-126 Td, squarely in the 3-6 eV band) and displacement-dominant behavior (96.5%) outweigh the frequency penalty in the current weighting. It refused to trade film quality for band compliance.

What the ranking does resolve is the winding trade-off at fixed L. Candidate #1 wins because fat, few-turn AWG18 (80 turns, 0.2Ω) gives the highest coil Q (886) and tank Q (26.4), so the cleanest ×26.4 voltage magnification, 316V on the film, 126 Td — the deepest into the window. Adding turns (#2, #3) or thinning wire (#4, #5) only raises AC resistance, drops Q, and walks Td back down. Copper loss is the whole story here.

I'm adopting #1, but with the honest caveat that it does NOT meet my own drivability goal — it's a Td/Q champion, not a frequency solution. This model never actually populated the intermediate inductances I asked for.

Next session: force L to 0.5, 1.0, 1.5mH explicitly and re-check whether 120 Td survives as f_r falls, keeping AWG18 fat windings.