Constrained sheath optics for high thrust density, low specific impulse ion thrustersThe results of an experimental study showing that a contoured, fine wire mesh attached to the screen grid can be used to control the divergence characteristics of ion beamlets produced at low net-to-total accelerating voltage ratios are presented. The influence of free and constrained-sheath optics systems on beamlet divergence characteristics are found to be similar in the operating regime investigated, but it was found that constrained-sheath optics systems can be operated at higher perveance levels than free-sheath ones. The concept of a fine wire interference probe that can be used to study ion beamlet focusing behavior is introduced. This probe is used to demonstrate beamlet focusing to a diameter about one hundreth of the screen grid extraction aperture diameter. Additional testing is suggested to define an optimally contoured mesh that could yield well focused beamlets at net-to-total accelerating voltage ratios below about 0.1.
Document ID
19870052362
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Wilbur, Paul J. (Colorado State Univ. Fort Collins, CO, United States)
Han, Jian-Zhang (Colorado State University Fort Collins, United States)