Dynamics of nonlinearly interacting magnetic electron drift vortex modes in a nonuniform plasma

Abstract

A simulation study of dynamical evolution of nonlinearly interacting two-dimensional magnetic electron drift vortex (MEDV) modes in a nonuniform plasma is presented. Depending on the equilibrium density and temperature gradients, the system can either be stable or unstable. The unstable system reveals spontaneous generation of magnetic fields from noise level, and large-scale magnetic field structures are formed. When the system is linearly stable, one encounters MEDV mode turbulence in which there is a competition between zonons (zonal flows) and streamers. For large MEDV mode amplitudes, one encounters the formation of localized and small-scale magnetic vortices and vortex pairs with scale sizes of the order of the electron skin depth. The MEDV turbulence exhibits nonuniversal (non-Kolmogorov-type) spectra for different sets of plasma parameters. The relevance of this work to laboratory and cosmic plasmas is briefly mentioned.