GB1521327A - High-frequency plasma drive - Google Patents

Abstract

1521327 Jet propulsion plant MESSERSCHMITT-BÍLKOW-BLOHM GmbH 5 Nov 1975 [16 Nov 1974] 45940/75 Heading F1J [Also in Division H1] A high frequency plasma drive comprises a “ # high frequency generator 7 coaxially coupled to a “ # resonator 8 which forms part of an open ended discharge chamber 11 in which a uniform magnetic field is produced by coil 15 and in which propellant gas is ionized and the plasma subsequently accelerated, wherein the intensity of the magnetic field in the discharge chamber, the frequency of the generator and the density of the plasma are so arranged that the dielectric constant of the plasma is negative whereby Lorentz forces acting on the plasma are subject to resonance-like intensification. As shown, the generator and discharge chamber are formed by coaxial tubes 2, 3 inter-connected by a disc 4, all of silver plated copper, the generator 7 being energized by a planar-triode 5 through an isolating capacitor 6. The cylindrical cavity circuits i in the generator and resonator interconnected through an inductive coupling loop 9. Mercury vapour is introduced through a distributer 12 into the discharge chamber 11 which is closed at one end by a quartz disc 10. When drive is put into operation the gas discharge ignites in the electrical field of the resonator without a special ignition device and the plasma is accelerated from the chamber by Lorentz forces. The mechanism of this acceleration and the factors influencing it are theoretically discussed in some detail. In a modification, Fig. 2 (not shown), a quartz plasma boundary anchor (21) followed by acceleration and retardation electrodes (22) is provided at the open end of the resonator to accelerate the ions, which may be neutralized by electrons from an axially disposed hollow cathode (23). The current density may be varied by means of the intensity of the magnetic field.