Patent ID: 6215124
Filing Date: 2001-04-10
Classification: F03H

Abstract:
An ion accelerator with closed electron drift having an annular gas discharge area including an exit end, discharge of gas through the exit end defining a downstream direction, said accelerator comprising:an inner magnetic pole located at the inside of and encircled by the annular gas discharge area adjacent to the exit end;an outer magnetic pole located at the outside of and encircling the annular gas discharge area adjacent to the exit end, the inner and outer magnetic poles having outer faces extending transversely of the downstream direction remote from the discharge area at the exit end;a magnetic field source for producing a generally radially extending magnetic field between the inner pole and the outer pole in the vicinity of the exit end of the gas discharge area;an anode located upstream of the exit end of the gas discharge area;a gas source for supplying an ionizable gas to the gas discharge area for flow in a downstream direction toward the exit end;an electron source for supplying free electrons for introduction toward the exit end of the gas discharge area in a generally upstream direction;an electric field source for producing an electric field extending from the anode in a downstream direction through the exit end to a cathode, interaction between the ionizable gas from the gas source and free electrons from the electron source producing ions accelerated in a downstream direction by the electric field to produce a propelling reaction force, the electric field source including a plurality of electrodes located at the magnetic pole outer faces and biased to potentials different than the potential of the anode or the potential of the cathode to influence the electric field in the area of the exit end.