Pulsed electrothermal thruster
AssigneeGT-Devices
InventorsRodney L. Burton, Yeshayahu S. A. Goldstein, Derek A. Tidman, Niels K. Winsor
Life of this patent
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Abstract
A plasma electrothermal thruster includes a capillary passage in which a plasma discharge is formed and directed out of an open end of the passage into a supersonic nozzle. Liquid supplied to the capillary passage becomes partially atomized to cool a confining surface of the passage. The plasma discharge is formed as the atomized liquid flows out of the open end into a supersonic equilibrium nozzle. The discharge can have a duration greater than the two way travel time of acoustic energy in the capillary to cause the plasma to flow continuously through the nozzle during the time of the discharge pulse.
Claims9
An electrothermal thruster adapted to be mounted on a mass to be propelled comprising means for forming a capillary passage having an elongated plasma confining surface that is an outer boundary for plasma in the passage, the passage having an open end, electric means for forming a plasma discharge in the capillary passage, the capillary passage being arranged so that the plasma is ejected from the capillary passage only out of the open end, the ejected plasma being a thrust source for the mass, the plasma in the capillary passage having a very high pressure on the order of 1000 atmospheres, the capillary being constructed so plasma flowing out of the open end has a tendency to be highly ionized and dissociated, and a supersonic, equilibrium flow nozzle having an inlet positioned to be responsive to the plasma ejected from the open end, the nozzle having a high outlet to inlet area ratio and a high Reynolds number for achieving substantially adiabatic and equilibrium directed kinetic energy and relatively low ionization, dissociation and thermal energies.
An electrothermal thrust adapted to be mounted on a mass to be propelled comprising means for forming a capillary passage having an elongated plasma confining surface that is an outer boundary for plasma in the passage, the passage having an open end, means for forming a plasma discharge in the capillary passage, the capillary passaging being arranged so that the plasma is ejected from the capillary passage only out of the open end, the ejected plasma being the thrust source for the mass, the passage having a second end opposite from the open end, the means for forming the plasma discharge including electrode means for establishing the discharge longitudinally of the capillary passage between the inlet and the open end, and means for intermittently establishing the discharge for an interval that is at least equal to the two way travel time of the acoustic energy in plasma in the capillary passage between the second and open ends.
A method of operating an electrothermal thruster including a capillary passage having an elongated plasma confining surface that is an outer boundary for the plasma in the passage, the passage having an open end and a second end opposite from the open end, comprising electrically forming a plasma discharge longitudinally in the capillary passage between the open and second ends, the plasma discharge causing plasma to be formed in the passage and to be ejected only out of the open end of the capillary passage, the ejected plasma being a thrust source for a mass accelerated by the operating thruster, the discharge being intermittently formed for an interval that is at least equal to the two way travel time of acoustic energy in plasma in the capillary passage between the second and open ends.
Dependencies are inferred from the claim text.