Examination of the structure and evolution of ion energy properties of a 5 kW class laboratory Hall effect thruster at various operational conditions.

This thesis represents an effort to design, build, and characterize a 5 kW class Hall thruster for laboratory work. Particular attention was paid to plume because they cause interaction issues for satellite manufacturers and users due to their potential for damaging spacecraft surfaces and interfering with operations. A brief discussion of the history and physics of electric propulsion is provided, with more detail given for Hall thrusters. A procedure for Hall thruster design was developed based on Russian design equations and a parameter study of existing commercial thrusters. This method was used to design the University of Michigan/United States Air Force P5 5 kW class laboratory Hall thruster. This thruster was designed for easy diagnostic access and modification. Performance measurements of the P5 indicated that it operated on par with commercial thrusters. To further characterize and analyze the ion acceleration structure of the P5, an extensive study of ion energy distributions and ionic species composition was made using the Molecular Beam Mass Spectrometer, a time-of-flight mass spectrometer with a 45-degree electrostatic energy analyzer. Measurements were taken at various angles with respect to the thruster at two axial locations in order to gain insight into the acceleration structure and how it is affected by the Hall thruster's annular configuration. These measurements were performed at several operating conditions to investigate how changes to the discharge voltage and current affected the acceleration structure. The effects of the facility on the data were also investigated. Ion energy distribution measurements indicated an overall inward focus to the plume of the P5, with many ions accelerated from the annular discharge chamber across thruster centerline. This structure was consistent at all operating conditions. Time of flight measurements indicated that the plume was composed primarily of singly ionized xenon, with detectable fractions of doubly, triply, and quadruply ionized xenon. It was found that by sampling the plasma in the near field, the effects of interactions with background neutral xenon could be minimized. Comparisons of the results with those obtained using laser induced fluorescence indicate agreement once the proper transformation of parameters is employed.Ph.D.Aerospace engineeringApplied SciencesPlasma physicsPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/132147/2/9959771.pd