Operating characteristics of a re-generable field emission cathode for low-power Electric Propulsion

Document Type

Conference Proceeding

Publication Date

1-1-2008

Abstract

This research investigates the discharge characteristics of a field-emission cathode for use in Electric Propulsion (EP) that has the ability to be re-generated when the emitter tip becomes damaged. Emitter tip re-generation is possible by using Taylor cone formation from an operating liquid-metal ion source (LMIS) in an effort to solidify, or quench, the ion emitting cone to preserve the sharp protrusion so that it can then be used for electron emission. Multiple electron emission I-V curves were taken after tips were formed by quenching the LMIS at ion discharge currents ranging from 1 to 25 μA. Fowler-Nordheim modeling was then used to estimate the emitter tip radii of each quenched emitter and showed that emitter tip radii decreased from about 45 nm from a tip quenched at 2 μA down to about 15 nm when quenched at 25 μA. Also, a 46 hour test was done using a single emitter that was quenched at 15 μA. Electron I-V curves were taken at the start, middle, and end of the test that showed no degradation in tip performance.

Publication Title

44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit

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