Plume Characteristics of the Busek 600 W Hall Thruster

Abstract

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) 23-05-2006 REPORT TYPE Technical Paper ABSTRACTTo better characterize the potential impacts of the operation of a Busek Company, Inc. BHT-HD-600 laboratory Hall thruster on spacecraft, a number of plume properties have been measured. These include current density using a Faraday probe, ion energy distribution using a retarding potential analyzer, and ion species fractions using an E x B probe. The BHT-HD-600 Hall thruster is a nominally 600 W xenon Hall thruster developed by Busek Co. Inc. for the U.S. Air Force Research Laboratory. Plume characterization of Hall thrusters is required to fully understand the impacts of thruster operation on spacecraft. Much of these plume data are vital inputs for numerical models that can then be applied to estimate the effect of the energetic plume on complex spacecraft geometries. Early measurement of plume properties, such as plume divergence, ion energy distribution, and species fractions, aids the timely transfer of Hall thruster technology to the user. The plume's ion beam was characterized by measurement of ion current density radial profiles, ion energy spectra and ion species fraction distributions. Measurements were recorded ±90 o off thruster centerline at 60 cm from the discharge. It was determined slight variations in anode potential and mass-flow produced a measurable effect on ion current density and plume divergence, experimentally showing an increase or decrease of ±15-20%. Ionic energy spectra demonstrated both inelastic and elastic scattering within the plume. The measurements reveal significant populations of multiplycharged ions in the plume. E x B probe measurements show surprisingly ion species fraction angle dependence.

Comparison of Numerical and Experimental Time-Resolved Near-Field Hall Thruster Plasma Properties

“…where ( ) is the energy distribution of species i; ( ) is the excitation cross sections for a particle i, with energy , with a particle j to produce emission at λ ; and is the velocity of particle i. Excitation cross sections for neutral-electron and neutral-ion collisions are determined empirically from Chiu et al 18 and Sommerville 19 . Assuming a Maxwellian electron energy distribution, is determined as a function of the electron temperature, .…”

High Throughput 600 Watt Hall Effect Thruster for Space Exploration

“…6,7 Testing of the breadboard model BHT-600 in both individual and clustered configurations has been reported. Published research discusses thermal characterization, 8 performance measurements, 9 discharge oscillations, 10 erosion modeling, 11 plume characterization, 12,13,1415,16 and the ion velocity distribution. 17,18 In moving from the breadboard model to the engineering model, the magnetic field was modified to push the plasma discharge downstream, substantially increasing thruster lifetime.…”

Collisionless electron cooling in unmagnetized plasma thruster plumes

“…Plasma plumes of different thrusters (e.g. Hall effect thrusters [10][11][12][13][14][15][16] and gridded ion thrusters [17][18][19][20][21] ) are routinely characterized in detail in laboratory experiments using plasma probes and optical diagnostics. These experiments can faithfully recover the properties of the primary ions created inside the plasma thruster.…”