Two-dimensional electron-magnetohydrodynamic nonlinear structures

Two-dimensional coherent electromagnetic structures involving the dynamics of the electron population in a quasineutral plasma with immobile ions are described. These structures consist of small scale magnetic vortices that propagate at a constant velocity. The dispersion relations of dipolar and tripolar vortices and of dipolar vortices and of vortex chains are given. The magnetic field of these vortices is three-dimensional. In addition, stationary quadrupolar vortices are described that are formed in the neighborhood of an X-point of the background configuration. (C) 2000 American Institute of Physics. [S1070-664X(00)01303-3].