Continuous ionization injector for low pressure gas discharge device

Claim 1

A crossed-field switch tube having an igniter, said crossed-field switch tube comprising: a substantially cylindrical tubular cathode, a substantially cylindrical anode positioned within said cathode and defining an annular interelectrode space therebetween, said anode and said cathode being electrically insulated from each other and being connectable to a source of electrical potential, a gas at sub-atmospheric pressure within said interelectrode space, the gas pressure being such, in relation to the interelectrode space dimension, that the conditions are outside the conductive area of the Paschen curve, a magnet positioned to selectively provide a magnetic field in the interelectrode space so that in the presence of the magnetic field an electron in the interelectrode space is caused to annularly spiral in the annular interelectrode space to provide cascading ionization and conduction between said anode and said cathode, said igniter comprising: a cold cathode plasma discharge chamber having a cathode surface, a thin wire anode mounted within said discharge chamber and spaced from said cathode, means for connecting an electric potential between said cathode surface and said thin wire anode, and an opening between said discharge chamber and said interelectrode space so that gas at subatmospheric pressure in said interelectrode space is in said discharge chamber, so that upon application of discharge voltage between said cathode surface and the thin wire anode a plasma discharge is produced in said plasma discharge chamber so that electrons and ions from the plasma discharge pass through the opening into the interelectrode space to produce initial ionization therein so that upon application of an interelectrode potential and an adequate magnetic field in the interelectrode space a crossed-field discharge is initiated.