Dynamics of uniform vortex patch with a point vortex

Abstract

Vortex dynamics in two-dimensional inviscid, incompressible fluids are isomorphic to the dynamics of strongly magnetized guiding center plasmas restricted to E /spl times/ B motion. In this paper, we exploit this analogy and study the dynamics of a uniform vortex patch with a point-like vortex using a particle-in-cell code. While the results show qualitative agreement with previous works in the linear regime when the normalized point vortex charge /spl Gamma/ is small, the dynamics shows many new features in the nonlinear regime: the point vortex fangs out the patch and moves toward the center, wrapping the patch around itself while setting up regions of zero vorticity as it moves.