POLARIZED SUPERSONIC PLASMA-FLOW SIMULATION FOR CHARGED BODIES SUCH AS DUST PARTICLES AND SPACECRAFT

When an object such as a dust particle or spacecraft is immersed in a plasma flowing at a supersonic speed, an asymmetric screening potentia l forms around that object. The asymmetry is especially pronounced on the downstream side, with an ion rarefaction in the wake followed by a n ion focus region. This polarized screening potential helps explain r ecent laboratory results with dusty plasmas, where collective interpar ticle effects were shown to be asymmetric. Using an electrostatic flui d simulation with cold ions and Boltzmann electrons, we have simulated the flow around spherical and cylindrical bodies, with and without a negative potential bias. Here, the flow speed v(0) is assumed to be su personic (faster than ion acoustic) and mesothermal (v(Ti) much less t han v(0) much less than v(Te)) A numerical method is used, with a diff use object that simulates the ion loss and space charge on an object's surface. This works with one or many objects, of any shape. We presen t solutions for systems of one and two particles in a simulation box, with periodic boundary conditions that help reveal collective effects.