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Spatially-Resolved Beam Current and Charge-State Distributions for the NEXT Ion EnginePlume characterization tests with the 36-cm NEXT ion engine are being performed at The Aerospace Corporation using engineering-model and prototype-model thrusters. We have examined the beam current density and xenon charge-state distribution as functions of position on the accel grid. To measure the current density ratio j++/j+, a collimated Eprobe was rotated through the plume with the probe oriented normal to the accel electrode surface at a distance of 82 cm. The beam current density jb versus radial position was measured with a miniature planar probe at 3 cm from the accel. Combining the j++/j+ and jb data yielded the ratio of total Xe+2 current to total Xe+1 current (J++/J+) at forty operating points in the standard throttle table. The production of Xe+2 and Xe+3 was measured as a function of propellant utilization to support performance and lifetime predictions for an extended throttle table. The angular dependence of jb was measured at intermediate and far-field distances to assist with plume modeling and to evaluate the thrust loss due to beam divergence. Thrust correction factors were derived from the total doubles-to-singles current ratio and from the far-field divergence data
Document ID
20100033115
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Pollard, James E. (Aerospace Corp. El Segundo, CA, United States)
Diamant, Kevin D. (Aerospace Corp. El Segundo, CA, United States)
Crofton, Mark W. (Aerospace Corp. El Segundo, CA, United States)
Patterson, Michael J. (NASA Glenn Research Center Cleveland, OH, United States)
Soulas, George C. (NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 25, 2013
Publication Date
September 1, 2010
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
NASA/TM-2010-216790
AIAA Paper 2010-6779
E-17413
Meeting Information
Meeting: 46th Joint Propulsion Conference and Exhibit
Location: Nashvllle, TN
Country: United States
Start Date: July 25, 2010
End Date: July 28, 2010
Sponsors: American Inst. of Aeronautics and Astronautics, American Society for Electrical Engineers, Society of Automotive Engineers, Inc., American Society of Mechanical Engineers
Funding Number(s)
WBS: WBS 346620.04.08.02.02.01
Distribution Limits
Public
Copyright
Public Use Permitted.

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