The eikonal equation and meandering of spiral waves: A geometrical approach

The eikonal equation supports the rotating spiral wave with the core rotating periodically. It is shown that this pivoting constraint can be removed by prescribing appropriate motion of the core compatible with the global motion of the spiral. A geometrical approach is presented for investigating the phenomenon not previously solvable by means of the eikonal equation: the motion of spirals whose tips are not fixed, but meandering.