Nonlinear large scale current structures in simulations of Electron Drift Instability

Electron Drift Instability (EDI) driven by the electron current due to the external electric field perpendicular to the magnetic field has been actively studied as a robust source of fluctuations and transport in $E/times B$ plasma sources. The basic linear instability occurs on the short length scale determined by the cyclotron resonance conditions which may be modified by nonlinear broadening and other geometrical effects. Many simulations todate report the coherent structures in the mm range associated with such EDI modes and their modifications. Here, we report the excitation of nonlinear two-dimensional long wavelength structures in the anomalous electron current (current vorticies) that are observed in the simulations of an azimuthally wide system. These structures are moving with roughly the $E\times B$ velocity and occur at the edges of the azimuthal electron $E\times B$ beam presumably due to the shearing effects. The current vorticies provide large contribution to the net (averaged) anomalous electron current.