Modeling of the charged particle transport process in a decaying plasma with a Π-type electrode configuration

Abstract

In this paper, a two-dimensional (2D) kinetic modeling on the ion extraction process in a decaying barium plasma with a Π-type electrode configuration is performed using an open-source particle-in-cell computer code, WARP. An important phenomenon predicted by the 2D simulation is that the electric potential at the plasma bulk is lower than that of the anode after the transient sheath forms. This is quite different from the commonly believed modeling results using the electron-equilibrium fluid model. The appearance of this reduced voltage drop between the plasma bulk and cathode surface (ΔV) is explained physically from the global balance of the extracted ion and electron currents. The analytically predicted values of ΔV are qualitatively consistent with those from the kinetic modeling under different initial plasma densities and externally applied voltages. This work is helpful for optimizing the ion extraction efficiency with a Π-type electrode configuration in future research.