Non-ambipolar Electron Source

Award Information
Agency: National Aeronautics and Space Administration
Branch: N/A
Contract: NNC06CB42C
Agency Tracking Number: 050300
Amount: $100,000.00
Phase: Phase I
Program: STTR
Awards Year: 2006
Solicitation Year: N/A
Solicitation Topic Code: N/A
Solicitation Number: N/A
Small Business Information
8123 Forsythia Street Suite 140, Madison, WI, 53562
DUNS: 612389572
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 Noah Hershkowitz
 Principal Investigator
 () -
Business Contact
 Gregory Piefer
Title: Business Official/President
Phone: (608) 345-3779
Research Institution
 University of Wisconsin-Madison
 Stepahnie Gray
 301 N. Whitney Way
Madison, WI, 53706
 (608) 263-4970
 Nonprofit college or university
A device to produce electron beams from magnetized plasma created with rf fields combined with electron extraction by electron sheaths is proposed. The source can provide electrons for neutralizing positive ion beams emerging from ion thrusters or as a generic electron source. With hollow cathode sources currently employed to provide neutralizing electrons, operation is limited in time and/or current density by cathode deterioration. RF electron sources provide an alternative approach that does not consume electrode material. The current from this Non-ambipolar Electron Source (NES) exceeds the current normally extracted from conventional rf plasma sources by a factor of (mi/me)1/2 where mi and me are the ion and electron mass. Ions are lost to a negatively biased conducting cylinder with area Ai chosen to be Ai ≥ (mi/me)1/2 *Ae where Ae is the electron extraction area. Slots in the conducting cylinder allow the cylinder to serve as a Faraday shield to reduce capacitive coupling from the antenna to the plasma. Proposed phase 1 design improvements should result in electron currents comparable to hollow cathode sources with lower neutral gas flow in the inductive discharge phase and higher currents with helicon operation. Phase 2 will develop prototype sources suitable for spacecraft testing.

* Information listed above is at the time of submission. *

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