PID Diffusion Front & Arrhenius Diagnostics (2D)

This is the 2D-native counterpart to the 3D Potential-Induced Degradation module simulator. Rather than rendering a cell grid in a 3D scene, it simulates the ion migration mechanism directly: hundreds of sodium ions each perform an independent 1D Brownian random walk from the frame edge, and by the reflection principle their ensemble survival distribution reproduces the exact same erfc drift-diffusion front used by the 3D model — visible here as a live concentration profile converging out of the particle swarm rather than a formula placing particles. A companion Arrhenius panel plots ln(D) against 1000/T with the current operating point marked, and a growing √t linearization strip chart checks the front depth against the straight-line signature that real Fickian diffusion is supposed to produce, turning the same physics used in the 3D degradation model into a genuinely 2D chart-and-particle diagnostic instrument.