Kinetic simulation and theory of plasma shear-flow instabilities relevant to magnetically insulated transmission lines

Electron sheath flow in magnetically insulated transmission lines (MITL) is susceptible to Kelvin-Helmholtz type instabilities. Additionally, contaminant material on the electrode surfaces forms a plasma that can travel across the anode-cathode gap. The transport of contaminant plasmas can be enhanced by these electron shear-flow instabilities, reducing the efficiency of the MITL [Phys. Plasmas 22, 032101 (2015)]. In this work, a 2D particle-in-cell (PIC) simulation is used to study the shear-flow instabilities. The instability is studied by modelling a planar, crossed-field diode with electron shear flow and a fixed anode voltage. We investigate the effects of a contaminant plasma layer on the cathode and/or anode surfaces on the shear-flow instabilities and plasma transport. For PIC benchmarking and additional analysis, the theoretical analysis by Davidson is adopted with density profiles relevant to simulation results [Phys. Fluids 27, 2332-2345 (1984)].

This work is supported by the DOE NNSA LRGF under cooperative agreement DE-NA0003960. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525