Planar crossed-field plasma switch and method

A method for providing a switchable current path through a plasma, comprising the steps of:

• adjoining an ionizable gas with a cold cathode;
• establishing a magnetic field in said ionizable gas so that, in at least a portion of said ionizable gas, said magnetic field surrounds a magnetic-field axis and is radially oriented outward from said axis;
• establishing an electric field that is axially oriented in said ionizable gas portion along said magnetic-field axis so that said axially-oriented electric field and said radially-oriented magnetic field direct secondary electrons from said cathode along cycloidal paths in said ionizable gas portion to generate a plasma source;
• and
• selectively removing and forming an electrostatic shield between said plasma source and an anode to thereby initiate and terminate a plasma path between said plasma source and said anode, said plasma source and said plasma path forming said current path between said cathode and said anode.

A cold cathode, crossed field switch arranged about a switch axis and containing an ionizable gas, comprising:

• a magnet system having magnets arranged in coplanar and concentric magnet rings about said switch axis to generate a magnetic field which surrounds said switch axis and is radially oriented outward from said switch axis;
• a planar electrode system which includes:
• a) a planar cold cathode;
• b) a planar anode spaced from said cathode and positioned with said cathode between said anode and said magnet system;
• c) a planar source grid positioned between said anode and said cathode and spaced from said cathode to form a source grid-to-cathode gap which substantially contains said radially-oriented magnetic field, said source grid and said cathode arranged to generate an axially-oriented electric field in said source grid-to-cathode gap in response to a source voltage applied to said source grid, said radially-oriented magnetic field and said axially-oriented electric field directing secondary ions from said cathode along cycloidal paths in said ionizable gas to generate a plasma source in said source grid-to-cathode gap;
• and
• d) a planar control grid positioned between said anode and said source grid, and spaced from said anode to form a control grid-to-anode gap, said control grid arranged to selectively receive first and second control voltages to initiate and terminate a plasma path which connects said plasma source and said anode across said control grid-to-anode gap;
• a cylindrical dielectric member that supports said planar anode and contains said ionizable gas;
• and
• an annular shield member which extends from said anode into said control grid-to-anode gap to shield said dielectric member from sputtering impurities.