Orientation independent ignitron with grooved cathode

An orientation independent ignitron, comprising:

• a generally annular cathode having a plurality of spaced annular grooves having concave sections on its inner surface;
• an anode coaxially disposed within said cathode and having an anode surface spaced from and facing said inner cathode surface,
• means for cooling said cathode sufficiently so that liquid metal vapor between said cathode and anode condenses as a film retained on said cathode inner surface by surface tension and forms generally annular reservoirs within the concave sections of said grooves, and
• means for applying a voltage differential between said cathode and anode sufficient to sustain a metal vapor arc between said anode and the liquid metal coated cathode for a pulse period.

An orientation independent ignitron, comprising:

• a generally annular cathode having a plurality of spaced annular grooves on its inner surface, said inner cathode surface being characterized by generally convex section bounding successive grooves,
• an anode disposed within said cathode and having an anode surface spaced from and facing said inner cathode surface,
• means for cooling said cathode sufficiently so that liquid metal vapor between said cathode and anode condenses as a film retained on said cathode inner surface by surface tension and forms generally annular reservoirs within said grooves,
• means for applying a voltage differential between said cathode and anode sufficient to sustain a metal vapor arc between said anode and the liquid metal coated cathode for a pulse period, and
• a plurality of igniters adjacent at least some of said cathode grooves for generating a plasma from the liquid metal on said cathode surface to initiate conduction between said cathode and anode, wherein said igniters extend inwardly through the cathode to locations at approximately the apices of respective convex sections.

A method of wetting the inner surface of a generally cylindrical orientation independent ignitron cathode with a liquid metal film, said inner cathode surface having a plurality of generally annular grooves facing and spaced from an anode which is interior to the cathode, comprising:

• positioning said cathode on its side with said grooves generally vertical,
• accumulating liquid metal reservoirs at the lower ends of said grooves,
• establishing metal vapor arcing between said anode and the liquid metal within said grooves,
• sustaining said arcing with a sufficient current density and for a sufficient period of time so that said liquid metal reservoirs flow and wet the adjacent surface of said grooved cathode, liquid metal evaporates from said reservoirs and condenses on the remainder of the grooved cathode surface, and said arcing progresses to the areas of the cathode surface upon which liquid metal has condensed to wet the condensed liquid metal against the cathode surface and form a liquid metal film retained on substantially the entire grooved cathode surface by surface tension.

An orientation independent ignitron, comprising:

• a cathode having a surface with a plurality of spaced grooves, said grooved cathode surface being characterized by generally convex sections bounding successive grooves,
• an anode having surface spaced from and facing said cathode surface,
• means for cooling said cathode sufficiently so that liquid metal vapor between said cathode and anode condenses as a film retained on said cathode grooved surface by surface tension and forms reservoirs within said grooves,
• means for applying a voltage differential between said cathode and anode sufficient to sustain a metal vapor arc between said anode and the liquid metal coated cathode for a pulse period, and
• a plurality of igniters adjacent at least some of said cathode grooves for generating a plasma from the liquid metal on said cathode surface to initiate conduction between said cathode and anode, said igniters extending through the cathode to locations at approximately the apices of respective convex sections.