3D Multi-Fluid MHD Simulation of the Early Time Behavior and Cross-Field Propagation of an Artificial Plasma Cloud in the Bottom Side Ionosphere

Plasma injection experiments in the ionosphere and magnetosphere have been carried out and studied over the previous forty years to better understand many fundamental large-scale plasma phenomena. Typically, this involves the release of a neutral gas susceptible to significant photoionization. The plasma coupling to the environment is of special interest as it allows measurement of large-scale plasma waves, instabilities, diamagnetic cavities, and parallel electric fields, the testing of Alfven's Critical Ionization Velocity (CIV), and the measurement or modification of environmental parameters. It is well known that the motion of an artificial ion cloud across the magnetic field produces a polarization field with and ExB drift in the direction of the initial cloud motion. The cross-field polarization current couples momentum to the background plasma causing the cloud to brake or “skid” before coming to rest. It became apparent soon after the AMPTE (1984) and CRRES (1990) releases that injected plasma clouds displayed anomalous skidding characteristics in disagreement to many numerical simulations. A multi-fluid five-moment magnetohydrodynamic (MHD) model to simulate an artificial barium cloud release perpendicular to the magnetic field in the lower ionosphere is presented. Preliminary results show new cloud skidding features that relate the ion cyclotron frequency, cloud release mass, release velocity, and ionization rate in the momentum equation of motion.