Path Widening at the Polarity Inversion Line: Sign-Resolved Helicity Contact Structure and the Dispersion of Absolute Current Helicity as Independent Flare-Onset Coordinates

Abstract Active-region scalar indices of magnetic non-potentiality measure how much free energy and current an active region contains, but they do not by themselves determine where or when release begins. Motivated by a controlled fluid-dynamical result that the distribution of local helicity distinguishes vortex states whose volume integral is matched (Pan 2026b), we ask two corresponding solar questions: (i) at matched activity level, does the sign-resolved local helicity structure at the polarity inversion line (PIL) distinguish flare-onset frames from non-onset frames; and (ii) does this phase-space channel count correlate with the physical-space dispersion of absolute current helicity, as predicted by a pathwidening rather than threshold-lowering mechanism? The physical picture is path widening: within a fixed-helicity sector, only charge-compensated configurations are admissible, so the number of admissible opposite-helicity contact configurations grows with the balance of the two sign reservoirs and not with their total magnitude. Two operational coordinates follow — the minority helicitysign share \(s_{P}\) , the opposite-sign interface frontage L , and the local phase-space multiplicity Λ \(\Lambda^{*}\) — all computed pixel-wise on HMI/SHARP cylindrical equalarea vector maps. Over the 27 native-cadence frames of NOAA 12673 on 2017 September 6 (containing the X2.2 confined and X9.3 eruptive onsets), we run four pre-declared tests. In a matched-intensity pair test in which onset and non-onset frames are paired only when TOTUSJH and USFLUX agree to within \(|\Delta log _{10}| ≤0.02\) , the two onset frames exceed every matched non-onset frame in \(s_{P}\) , in the binary entropy \(H(s_{P})\) ,in L ,and in \(\Lambda^{*}\) , over 20 matched comparisons. A placebo calibration that treats every frame as a candidate onset finds only 3 of 27 frames attaining a perfect win fraction, giving an exact \(p=0.0085\) . Most importantly, at fixed TOTUSJH the local phase-space multiplicity Λ \(\Lambda^{*}\) is strongly anti-correlated with the absolute current helicity index ABSNJZH (partial Pearson