Chronoamperometry: Fick's-Law Diffusion Profile Solver

This simulator solves the same electrochemistry problem as its 3D companion — chronoamperometry, where a working electrode instantly consumes analyte ions the moment they touch its surface — but does so as an explicit 2D finite-difference solution of Fick's second law rather than a particle visualization. A 320-point concentration grid is stepped forward in time every frame, the electrode current is read directly off the local concentration gradient via Fick's first law, and the result is plotted live against the closed-form Cottrell equation I(t) ∝ t^-1/2 so you can see the numerical solver and the analytical prediction converge in real time. Tune the bulk concentration, diffusion coefficient and electrode area to see how each reshapes the depletion profile and the resulting current-decay curve.