High performance hypervelocity plasma jet simulation and design optimization

We report on numerical design studies of shaped coaxial plasma jets. HyperV Technologies has been actively engaged in a program of designing, building and testing a new class of plasma jet design. The goal is to build a plasma jet capable of accelerating dense compact plasma masses exceeding 200 μg to greater than 200 km/s with high Mach number. Such dense hypervelocity plasma jets have a variety of promising uses including momentum injection, plasma refueling, and as drivers for magnetized target fusion. Historically, plasma jets have usually been straight coaxial designs. However, such devices are subject to a blow-by instability that severely limits performance. Our numerical studies have found that by properly shaping the electrodes the blow-by instability can be ameliorated and the design objectives achieved. These studies show that in order to maximize performance, each stage of the pulse discharge, including armature formation, acceleration and detachment from the inner electrode, and transport of the plasma blob must be optimized. The primary tool for these design studies has been the Mach2 2-½ D MHD code. In addition, the LSP code is utilized to look at various microphysics problems dealing with the acceleration of the plasma blob. As part of this program, the LSP code is being extended to solve the EMHD equations and incorporate a new highly accurate radiation transport model. This tool will be capable of accurately modeling the acceleration physics over practical time scales as well as study the dynamics of magnetized target fusion.