Two-fluid and kinetic study of sheared flow instabilities in non-uniform collisionless plasmas in ExB configurations

The transport properties of low-density non-uniform ExB plasmas have important consequences in pulsed power systems such as the Z facility, where current is delivered to the load via magnetically insulated transmission lines. Formation of low-density plasmas within these ExB configuration transmission lines is known to give rise to parasitic currents, which interfere with load dynamics and prevent scaling of pulsed power experiments to higher energy densities. To understand the mechanisms that lead to current loss and plasma transport, the ExB environment is investigated using two-fluid plasma theory and high-order continuum kinetic Vlasov-Poisson simulations in (x,y,vx,vy) phase space. The computational study is facilitated in part through the initialization of self-consistent kinetic equilibria. Sheared flows are found to be present and density gradients are found to strongly influence dynamics and transport. The kinetic Kelvin-Helmholtz instability, induced by ExB sheared flow, is studied in detail as a candidate transport mechanism. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-753410