Self-regenerating nanotips for low-power electric propulsion (ep) cathodes
AssigneeMichigan Technological University
InventorLyon Bradley King
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Abstract
Spindt-type field-emission cathodes for use in electric propulsion (EP) systems having self-assembling nanostructures that can repeatedly regenerate damaged cathode emitter nanotips. A nanotip is created by applying a negative potential near the surface of a liquefied base metal to create a Taylor cone converging to a nanotip, and solidifying the Taylor cone for use as a field-emission cathode. When the nanotip of the Taylor cone becomes sufficiently blunted or damaged to affect its utility, the base metal is re-liquefied by application of a heat source, a negative potential is reapplied to the surface of the base metal to recreate the Taylor cone, and a new nanotip is generated by solidifying the base metal.
Claims19
An apparatus comprising
- an electric propulsion thruster;
- a field-emission cathode comprising a base metal;
- an electrode downstream from the field-emission cathode;
- and
- a heat source in contact with the field-emission cathode.
A method for developing field-emission cathodes for use in electronic propulsion systems, the method comprising:
- delivering a base metal to an extraction site;
- applying a negative bias to an electrode downstream from the extraction site to create a Taylor cone having a cone tip in the base metal at the extraction site;
- solidifying the base metal to preserve the Taylor cone;
- applying a positive bias to the electrode so that the Taylor cone functions as a field-emission cathode;
- regenerating the cone tip after it has become damaged by re-liquefying the base metal, applying a negative bias to the electrode to regenerate the Taylor cone tip, and re-solidifying the base metal to preserve the cone tip,
- wherein the field-emission cathode is used in an electric propulsion system.
Dependencies are inferred from the claim text.