FitzHugh-Nagumo model. "Center of rotation" dynamics

a b ε dt dx path

it delay fps t
On 2D plane positive u values are displayed by the red color (negative "tail" is not shown). v values are displayed by the green color. This script uses simple explicit algorithm and 512×512 float32 textures with the Neumann (CLAMP_TO_EDGE) boundary conditions. It makes 2 it time steps per frame.

For t > 200 (after spiral formation) the script begins to plot the path of the spiral wave tip (the white curve). The center of rotation path is the yellow curve. It is determined as intersection of tu = 0 and tv = 0 curves (i.e. the point where spiral is constant). Set b = 0.3 to get a plain spiral.
1024×1024 grid.

Heart rhythms     updated 11 Mar 2012