2D axisymmetric Particle-In-Cell study of a hollow cathode and its near plume region*

Hollow cathodes are efficient plasma sources and have been used in a wide variety of applications including electric propulsion, surface processing and plasma-material interaction studies.

Despite continuous progress, nonclassical processes such as the anomalous resistivity remain difficult to predict in hollow cathodes. Indeed, current modelings that are often based on a fluid or hybrid approach, rely on semi-empirical data and so need to be adjusted for each new configuration. Besides, the large mean free path downstream the orifice continues to challenge any fluid model.

In contrast, a Particle-In-Cell (PIC) method is well suited in this low-pressure regime and so it can help improve the current understanding of the plume dynamics that is highly dependent on the cathode orifice.

Therefore, in this work, we propose a fully kinetic axisymmetric two-dimensional study of a hollow cathode and its near plume region. The state-of-the-art open source code EDIPIC is used (https://github.com/PrincetonUniversity/EDIPIC-2D). Numerical results are consistent plasma expansion beams solutions, and we explore the influence of an imposed magnetic field on the plasma topology. Finally, we also investigate the impact of the orifice length-to-diameter aspect ratio on the plume dynamics.