Perovskite Ion-Migration Field & J-V Hysteresis (2D)

This is the 2D field companion to the 3D instanced-particle perovskite ion-migration simulator. Instead of animating individual ion spheres, it solves the identical drift-diffusion continuity equation as a continuum concentration field on a 90-cell spatial grid spanning the absorber thickness, using a stability-limited finite-volume update every frame. The field's own first moment stands in for the 3D view's averaged ion positions and drives the same voltage-screening / diode-current model, so the forward and reverse legs of the live J-V curve trace the same scan-rate-dependent hysteresis loop — but here you watch it as a density heatmap piling up against an electrode and relaxing back, a genuinely distinct 2D-native way to see the same physics.