Preliminary Report of Numerical Simulation of Intermediate Wavelength ExB Gradient Drift Instability in Ionospheric Plasma Clouds

摘要

Two-dimensional numerical simulations of intermediate wavelength (100-1000m) ExB gradient-drift instability in local unstable regions of large F region ionospheric plasma clouds have been performed, using an initial one-dimensional (y), cloud geometry, for plasma cloud density gradient scale lengths L = 3, 6, 10 km. For conditions typical of 200 km barium releases, we find that linearly unstable modes saturate by nonlinear generation of linearly damped modes along the y-direction (parallel to ExB drift). In the nonlinear regime, power laws are observed. These results are compared with recent in situ experimental measurements and theoretical predictions.