Kinetic simulation of magnetized plasma sheaths with oblique magnetic fields

Plasma-wall interactions are an essential factor for the performance of devices with applied magnetic fields. Especially for Hall thrusters, magnetrons, and tokamak diverters, there are areas where the magnetic field lines have a noticeable angle relative to the wall. These areas are of particular interest, since the oblique magnetic field can create unique sheath structures capable of modifying the expected wall fluxes, as well as secondary and field emission from the wall. In this work, a one-dimensional, particle-in-cell (PIC) simulation is applied to study plasma interactions with a dielectric wall for a range of magnetic field angles and ion-to-electron temperature ratios. Verified and validated with non-magnetized and magnetized cases, respectively, the PIC model illustrates the magnetized sheath structures and explores the distinctive electron velocity distribution functions in the pre-sheath region. Additionally, secondary electron emission effects are presented, where the applied magnetic field is shown to delay the formation of virtual cathodes in space-charge limited sheaths. Furthermore, a variety of boundary treatments for the plasma injection are assessed for cases with high magnetic field angles and cold ions.