Motion of extended vortices in an inhomogeneous pure electron plasma

The motion of extended vortices in a pure electron plasma with an inhomogeneous, centrally peaked, density in a Penning–Malmberg trap is studied by means of a two-dimensional electrostatic Eulerian code that solves the evolution equation for the electron distribution function in the guiding center approximation, coupled to the Poisson equation for the electrostatic potential. Vortices corresponding to electron density clumps propagate inward, as discussed in a recently proposed model for the case of point vortices, and carry inward both high and low density plasma. New, long-lived, structures consisting of a higher and of a lower density vortex pair are formed in the presence of a small amount of vorticity reconnection