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US 5,329,205 AGranted
High voltage crossed-field plasma switch
AssigneeHughes Aircraft Company
InventorsDan M. Goebel, Robert L. Poeschel, Ronnie M. Watkins
Life of this patent
Estimating the term…
Abstract
A CROSSATRON switch is capable of operating with voltages in excess of 100 kV by the use of a deuterium gas fill to increase the Paschen breakdown voltage, axial molybdenum cathode corrugations to provide a higher current capability, and a Paschen shield that is formed from molybdenum. The terminal curvature of the Paschen shield and of the adjacent portion of the anode are selected to establish a voltage stress at the curved Paschen shield surface within the approximate range of 90-150 kV/cm in response to a 100 kV differential.
Claims30
A plasma switch, comprising:
- a vacuum housing,
- a generally cylindrical cold cathode within said housing providing a source of secondary electrons, said cathode including a plurality of generally axially-directed corrugations around its interior surface,
- a generally cylindrical anode disposed inwardly of the cathode and extending axially beyond the limit of said cathode,
- a generally cylindrical source grid disposed between said anode and cathode,
- means for introducing an ionizable gas into the space between the cathode and source grid, said cathode and source grid maintaining a plasma therebetween in response to a predetermined voltage differential between them,
- a generally cylindrical control gird disposed between said source grid and anode for selectively enabling and terminating a plasma path between the cathode and anode, and thereby closing and opening the switch, in response to control voltage signals applied to the control grid,
- a magnet means configuring the plasma to a predetermined area between the cathode and anode, said magnet means producing a magnetic field that traps secondary electrons from the cathode and, together with a radial electric field, causes said electrons to travel in cycloidal orbits, and
- a generally cylindrical Paschen shield extending from said cathode adjacent to but spaced from a portion of said anode which extends beyond said cathode, said Paschen shield terminating in a first curved surface, the extended portion of said anode describing a second curved surface that is approximately concentric with and spaced from said first curved surface, the shapes of said curved surfaces and the spacing between then being selected to establish a voltage stress at said first curved surface within the approximate range of 90-150 kV/cm in response to a 100 kV differential between said anode and Paschen shield.
5 more elements
A plasma switch, comprising:
- a vacuum housing,
- a cold cathode within said housing providing a source of secondary electrons,
- an anode spaced from said cathode and extending beyond the limit of said cathode,
- a source grid disposed between the anode and cathode within the housing,
- means for introducing an ionizable ga into the space between the cathode and source grid, said cathode and source grid maintaining a plasma therebetween in response to a predetermined voltage differential between, them,
- a control grid disposed between said source grid and anode for selectively enabling and terminating a plasma path between the cathode and anode, and thereby closing and opening the switch, in response to control voltage signals applied to the control grid,
- a magnet means confining the plasma to a predetermined area between the cathode and anode, and
- a Paschen shield extending from said cathode adjacent to but spaced from a portion of said anode which extends beyond said cathode, said Paschen shield being formed from molybdenum, said Paschen shield terminating in a first curved surface, the extended portion of said anode describing a second curved surface that is approximately concentric with and spaced from said first curved surface.
5 more elements
A plasma switch, comprising:
- a vacuum housing,
- a generally cylindrical cold cathode within said housing providing a source of secondary electrons, said cathode including a plurality of generally axially-directed corrugations around its interior surface,
- a generally cylindrical anode disposed inwardly of said cathode,
- a generally cylindrical source grid disposed between the anode and cathode within the housing,
- means for introducing an ionizable gas into the space between the cathode and source grid, said cathode and source grid maintaining a plasma therebetween in response to a predetermined voltage differential between them,
- a generally cylindrical control grid disposed between said source grid and anode for selectively enabling and terminating a plasma path between the cathode and anode, and thereby closing and opening the switch, in response to control voltage signals applied to the control grid, and
- a magnet means confining the plasma to a predetermined area between the cathode and anode, said magnet means producing a magnetic field that traps secondary electrons from the cathode and, together with a radial electric field, causes said electrons to travel in cycloidal orbits,
- said axially corrugated cathode having a greater current density capability than a cathode of similar diameter but with a smooth electron emitting surface.
5 more elements
Dependencies are inferred from the claim text.