2D axial-azimuthal Particle-In-Cell benchmark for low-temperature magnetized plasmas

In applications such as ion sources or plasma processing, the gas pressure is relatively low and plasma confinement by a magnetic field is required. We call these plasmas “partially magnetized plasmas” because electrons are strongly magnetized, while ions are not. The magnetic field can be responsible for a variety of instabilities that are difficult to describe quantitatively. A kinetic description is needed to understand these instabilities but prior to use a Particle-In-Cell (PIC) code extensively, it is important to be sure of its correctness. Unit tests can be used to verify specific modules and benchmarks can be defined in a more global approach, such as the 1D Helium benchmark of Turner et al, in which 5 independent PIC codes were giving similar results. However, we needed here a simulation case that was closer to the complex physics of an ExB discharge. A 2D axial-azimuthal simulation case was chosen and the results of 7 independent PIC codes have been compared extensively (mean parameters and instabilities characteristics). A particular focus has been made on the dependance on number of particles per cell, as it has been recently shown to influence numerical results.