| 摘要 |
916,022. Discharge apparatus; ion sources. UNITED STATES ATOMIC ENERGY COMMISSION. May 25, 1959 [July 24, 1958], No. 17693/59. Class 39 (1). A high intensity energetic arc discharge is set up between a cathode and an elongated cup shaped anode and an axial magnetic field is maintained between the electrodes, feed, gas being supplied to the interior of both electrodes. The gas is preferably deuterium or tritium but may be air, hydrogen, argon, nitrogen or helium. There is complete ionisation of the feed gas within both cathode and anode and complete space charge neutralisation within or at the face of the cathode according as to whether the cathode is a hollow cup, Figs. 2-4 (not shown), or has merely an axial bore for the feed gas. The device may be a source of plasma or may replace the carbon arc in plasma-containment machines using dissociation of molecules, as in Specification 853,916. Alternatively positive ions accelerated towards the cathode, in the form of a collimated stream may be projected through an open end of the device to serve as propulsion means for a space vehicle, Figs. 3, 4 (not shown). The tungsten electrodes have thick copper jackets 3, 4 fitted with watercooling pipes 33. Floating cathode shields 5, 6 and a floating anode shield 7 are provided. Baffles 18, 19 are also floating, baffles 18 and 19 preventing recombined positive and negative ions respectively from flowing back to the arc and baffles 18 also trapping positive ions flowing towards the cathode. To start the arc the R.F. source 31 is switched on for the duration only of the starting interval. Alternatively a high D.C. potential is applied, or an auxiliary electrode adjacent the cathode is first made to touch it, then separated, then the auxiliary electrode is removed after striking. In Fig. 2 (not shown) the arc is a hollow cylinder, electrons being accelerated radially from the inside wall of the cathode. The arc is initiated at the facing tips of the cup anode and cathode after which the gas feed is reduced to make the discharge move inside the anode and cathode. In Fig. 3 (not shown) the hollow arc is enlarged at its central portion, the magnetic fields forming " mirrors " at each end. The cathode is supported by radial spokes. |
