Vacuum arc plasma thrusters with inductive energy storage driver
An apparatus for producing a vacuum arc plasma source device using a low mass, compact inductive energy storage circuit powered by a low voltage DC supply acts as a vacuum arc plasma thruster. An inductor is charged through a switch, subsequently the switch is opened and a voltage spike of Ldi/dt is produced initiating plasma across a resistive path separating anode and cathode. The plasma is subsequently maintained by energy stored in the inductor. Plasma is produced from cathode material, which allows for any electrically conductive material to be used. A planar structure, a tubular structure, and a coaxial structure allow for consumption of cathode material feed and thereby long lifetime of the thruster for long durations of time.
1. A vacuum arc plasma thruster having a coaxial geometry, said thruster comprising:
a power source having an anode output and a cathode output, said power source comprising:
a voltage source in series with an energy storage device in series with a switch, said switch having a terminal coupled to said anode output and a terminal coupled to said cathode output;
a coaxial plasma thruster including:
a tubular cathode electrode having an inner surface and an outer surface and a central axis;
a cylindrical anode electrode located substantially on said central axis;
an insulator placed between said tubular cathode inner surface and said cylindrical anode, said insulator having an area of preferred plasma formation between said anode electrode and said cathode electrode;
said preferred plasma formation area having a film of conductive material;
said power source anode output coupled to said anode electrode and said power source cathode output coupled to said cathode electrode.
2. The vacuum arc plasma thruster of claim 1 , where said energy storage device is an inductor.
3. The vacuum arc plasma thruster of claim 2 where said inductor is a magnetic core inductor.
4. The vacuum arc plasma thruster of claim 2 where said inductor is an air core inductor.
5. The vacuum arc plasma thruster of claim 1 where said insulator includes one of the materials alumina silicate or alumina.
6. The vacuum arc plasma thruster of claim 1 where said anode includes at least one of the materials titanium, copper, or gold.
7. The vacuum arc plasma thruster of claim 1 where said switch on time and said switch off time is varied in an aperiodic manner to control thrust.
8. The vacuum arc plasma thruster of claim 1 where said switch cycle time is fixed and said on time is varied to control thrust.
9. The vacuum arc plasma thruster of claim 1 where said switch on time is fixed and said switch off time is varied to control thrust.
10. The vacuum arc plasma thruster of claim 1 where said cathode carries a negative voltage compared to said anode after said switch is opened.
11. The vacuum arc plasma thruster of claim 1 where said cathode includes at least one of the materials carbon, aluminum, titanium, chromium, iron, yttrium, molybdenum, tantalum, tungsten lead bismuth, or uranium.