Numerical simulation of plasma sheaths inside the Hollow cathode discharge using the 2D-2V continuum-kinetic method

Plasma sheaths inside a hollow cathode (HC) are investigated numerically using a continuum-kinetic method. This approach allows for a self-consistent model that tracks the evolution of the distribution functions for both ions and electrons without the use of fluid assumptions. Ionization, charge-exchange, and thermalization collisions have been implemented to study the effects the sheaths have on the plasma discharge. The primary motivation of this work is to establish the feasibility of non-classical sheaths that are found near emissive surfaces inside of a HC. These structures may have a direct impact on the performance and operation of the HC due to changes in the thermal transport, erosion due to ion bombardment, and thermionic emission due to plasma-induced surface heating. The resulting simulations will represent, to the authors’ best knowledge, the first cleanly-resolved sheath structures inside a HC using a collisional kinetic model.