Observation of Instability driven propagating localized patterns in E×B discharges in 2D-axial azimuthal PIC-MCC simulations*

In low temperature E x B plasma discharges, Electron Cyclotron Drift Instability (ECDI) is a possible candidate to explain the anomalous electron transport across the magnetic field. Recently, a 2D axial azimuthal Particle-In-Cell benchmark study has been carried out using seven independently developed PIC codes with same specified geometry and simulation conditions (Charoy et al 2019 PSST. 28). In this work, we validate our independently developed parallel 2D PIC code with the benchmark case using the same geometry by applying a potential between anode and cathode, and a magnetic field perpendicular to the simulation domain. The simulations have been carried out with unscaled plasma density, real collisions are not considered, and the ionization profile is given as an input parameter as mentioned in the benchmark case. The constant ionization rate, calculated from maximum ion density, is provided at each time step. The state-of-the-art supercomputing facility has been used to accelerate the simulations involving hundreds of particles per cell while satisfying the stringent numerical PIC conditions. The FFT has shown two kinds of instabilities. The instabilities observed near the magnetic field region evolves with time and moves in the E x B direction, possibly ECDI. We also observe localized high-density patterns, believed to be induced by instabilities, moving across the magnetic field downstream along the axial direction between anode and cathode with a slightly higher velocity than ion acoustic velocity.  The generation of localized high-density patterns is observed near the edge of the given ionization profile.