Passive Optical Diagnostic of Xe-Propelled Hall Thrusters. II. Collisional-Radiative Model

A collisional radiative model is presented for analyzing the xenon-propelled Hall Thruster optical radiation based on apparent electron and ion-impact emission cross sections associated with lines in the visible and near-infrared region of the spectrum. The emission cross sections of selected near-infrared emission lines are incorporated in a collisional-radiative model. The effect of Stepwise excitation via metastable states on the derived line intensities for emissions from XeI 5p56p(6p') levels is evaluated. Meanwhile, visible XeII emissions are shown to provide plasma densities at high electron temperature conditions. The electron temperature and spatial ion number density distribution were determined from the luminescence spectra measured in the discharge and plume near-field plasma of the Hall thruster, the TSNIIMASH D-55 anode layer-thruster. The results are in good. agreement with the probe measurement data and simulations reported in the literature for the same thruster. The analysis of the Hall thruster XeI near-infrared spectra demonstrates that the neglect of ion-atom collisions results in an erroneous electron temperature determination at electron temperatures below 10 eV.

Published in Journal of Applied Physics, v99 p113305-1 through 113305-12, 2006. Prepared in collaboration with TSNIIMASH, Moscow, Russia. Sponsored in part by Air Force Office of Scientific Research (AFOSR), and by European Office of Aerospace Research and Development (EOARD). The original document contains color images.