Numerical simulation of steady-state and non-steady-state modes of a switching discharge in vacuum

This paper presents the results of a two-dimensional kinetic simulation of the switching of a vacuum gap by the cathode plasma flare. It is shown that, depending on the magnitude of the current passed through the vacuum gap, the gap can be switched in both a steady-state mode, in which the spark turns into a quasi-steady-state arc, and a non-steady-state quasi-periodic mode. The non-steady-state switching is associated with the occurrence of a current instability in the plasma, leading to rapid partial decay of the cathode flare plasma. In addition, it is shown that the instabilities arising in the plasma contribute to the broadening and shift of the energy distributions of the ions that have reached the anode. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/4.0/).