A xenon collisional-radiative model applicable to electric propulsion devices: II. Kinetics of the 6s, 6p, and 5d states of atoms and ions in Hall thrusters

Abstract

Electric propulsion devices of using xenon propellant are nowadays widely adopted for the space missions. A collisional-radiative (CR) model of xenon needs to be developed to understand the kinetic mechanisms of the excited and energetic species in these devices and also to support their optical diagnostics. Previously, due to limitations in the fundamental cross section data, Xe CR models focused on the atomic species; the ionic species, which also play important roles for the thrusters, were not studied in detail. In our previous paper, a fully relativistic Dirac B-spline R-matrix method was applied to calculate the relevant cross sections for electron collisions with the Xe+ ion. Based on these data, a comprehensive CR model—with the kinetics of metastable and excited levels of both Xe and Xe+ included—could be built. The calculated density distributions of atomic and ionic levels are examined by optical measurements in Hall thrusters in all of the four typical regions (near-anode-, ionization-, acceleration-, and plume-region). The special kinetic behaviors of the excited species are analyzed, and a set of rate coefficient data used for the Xe CR model is also provided.