IR-Assisted Discharge Initiation in Pulsed Plasma Thrusters
James E. Cooley and Edgar Y. Choueiri
Document type: AIAA Paper: AIAA-2002-4274, Presented at the
38th Joint Propulsion Conference, Indianapolis, IN, July 9-12, 2002.
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Abstract: It is demonstrated that a discharge can
be initiated in a pulsed plasma thruster (PPT) at an undervoltage by shining an IR laser pulse on the thrusterís backplate. The
technique has the potential for achieving uniform and erosion-free discharge initiation. Three candidate mechanisms
are investigated: thermionic emission, cathode vaporization, and gas desorption. Mass spectroscopic
measurements and theoretical calculations implicate water desorption from the backplate
as the likely explanation for the observed effects. It is then shown that while thermionic emission
was not operative in the experiments, it can be used as the basis of the design of a discharge initiator.