The ability of a magnetically filtered Faraday probe (MFFP) to obtain the ion current density profile of a Hall thruster is investigated. The MFFP is designed to eliminate the collection of low-energy, charge-exchange (CEX) ions by using a variable magnetic field as an ion filter. In this study, a MFFP, Faraday probe with a reduced acceptance angle (BFP), and nude Faraday probe are used to measure the ion current density profile of a 5 kW Hall thruster operating over the range of 300-500 V and 5-10 mg/s. The probes are evaluated on a xenon propellant Hall thruster in the University of Michigan Large Vacuum Test Facility at operating pressures within the range of 4.4×10-4 Pa Xe (3.3×10-6 Torr Xe) to 1.1×10-3 Pa Xe (8.4×10-6 Torr Xe) in order to study the ability of the Faraday probe designs to filter out CEX ions. Detailed examination of the results shows that the nude probe measures a greater ion current density profile than both the MFFP and BFP over the range of angular positions investigated for each operating condition. The differences between the current density profiles obtained by each probe are attributed to the ion filtering systems employed. Analysis of the results shows that the MFFP, operating at a +5 a solenoid current, provides the best agreement with flight-test data and across operating pressures.
J. L. Rovey et al., "Magnetically Filtered Faraday Probe for Measuring the Ion Current Density Profile of a Hall Thruster.," Review of Scientific Instruments, American Institute of Physics (AIP), Jan 2006.
The definitive version is available at http://dx.doi.org/10.1063/1.2149006
Mechanical and Aerospace Engineering
Keywords and Phrases
Plasma Magnetohydrodynamics; Plasma Probes; Plasma Transport Processes; Plasma accelerators; Plasma density; Xenon
Article - Journal
© 2006 American Institute of Physics (AIP), All rights reserved.