Off Design Simulation Results of Several Operating Conditions of the NEXT Discharge Chamber

Abstract

This paper provides a large number of computational results describing the discharge chamber operation for a number of thruster operating conditions of NEXT. In all, 15 thrust levels for NEXT have been simulated with a large number of results produced; however, only a representative sample of these results is included in this paper. These results are generated with a detailed PIC-MCC computer model of the discharge chamber developed at Wright State University in the period from 2004 to 2007. In the past this computer code has been shown to produce reasonable results for the NSTAR ion engine. With the Wright State discharge chamber code a large number of spatially resolved results can be obtained in a relatively inexpensive manner. The spatially resolved results include particle number density distributions, particle energy distributions, and particle current distributions. These distributions can be obtained for each of the particle types included in the analysis: neutrals, first ions, second ions, primary electrons, and secondary electrons. In addition, global operating parameters can also be obtained from this computer code. Global current results from the PIC-MCC computer model are within 57.4% of experimentally determined values and computational trends match those obtained from experiments.