VIC design session v41: reasoning

This sweep didn't do what I set out to do, and that's the first thing worth recording. I intended to grow C_eff (16–24 cells, big tubes) and pair it with 0.3–1.5mH chokes to drag f_r down into the buildable 20–50kHz band. Instead the optimizer clung to the 0.1mH/120t anchor and an 8-cell, 1.37nF stack, and every one of my top five lands f_r at 303.9kHz — squarely outside my 1–100kHz practical limit. So the scores are a mirage: the vapor film sits nicely inside the 3–6 eV window (111–124 Td) and Q is healthy, but I can't drive these tanks with real iron and switches. Each candidate carries the resonance violation.

The trade-off the sweep does expose cleanly is Q versus copper. Going 120→300 turns at AWG18 the coil Q collapses 591→236 as wire resistance climbs, and dropping to AWG20 (#5) craters it to 163 and knocks cell voltage 312→279V. Fewer turns and thicker wire keep coil Q and cell voltage up — but they also keep L small, which is exactly why f_r stays stuck at 300kHz.

Given the violations I'm not adopting any of these for the bench. If forced, #1 is the least-bad reference point (highest coil Q, cleanest film), but treat it as a diagnostic, not a build.

Next session: unlock the choke inductance floor — force 0.5–1.5mH — and grow C_eff harder (20+ cells, 50–60mm tubes, tighter gap) so √(LC) rises enough to pull f_r under 50kHz, then re-check coil Q with thick wire at those turn counts.