Evaluation of facility effects on ion migration in a hall thruster plume

Anested Faraday probe was designed and fabricated to assess facility effects in a systematic study of ion migration in a Hall thruster plume. Angular distributions of ion current density were studied at 8, 12, 16, and 20 thruster diameters downstream of a Hall effect thruster with four Faraday probe configurations at background pressures of 3 × 10-6, 1 × 10-5, and 3 × 10-5 torr. The effects of background facility neutrals were characterized and isolated, which enabled precise and accurate estimation of thruster ion beam current and plume divergence. A set of guidelines are recommended for Faraday probe design, experimental methodology, and data analysis that are aimed at minimizing uncertainty of far-field Faraday probe measurements. These guidelines were shown to reduce the experimentally derived ion beam current by 10-20%, compared with conventional analysis techniques, and to reduce measurement uncertainty to approximately ±3%. The reductions in measurement uncertainty and the increased capability to approximate the onorbit plume expansion from ground-based measurements are significant improvements that can be used for validation of numerical simulations and investigations of Hall thruster performance loss mechanisms. Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc.

Duke Scholars

Author Alec Gallimore Thomas Lord Department of Mechanical Engineering and Materia ...