External plasma gun

Abstract

The present device comprises, in a preferred embodiment, a permanent magnet assembly which is formed to closely resemble a doughnut with the inside surface defining an aperture having first and second ends. Said inside surface is formed concave to substantially resemble the letter 'C.' The permanent magnet provides magnetic flux from one end of the 'C' shaped inside surface to the other end. Hence the magnetic flux lines, or the magnetic flux field, form an enclosure with the concave configuration of the inside surface. An anode is located within the enclosure and is shielded by the magnetic flux field, i.e., the magnetic flux impedes the electrons from directly striking the anode. A cathode means is fitted over said first end of the aperture of the permanent magnetic assembly. A plasma exit plate, having a substantially large aperture therein, is fitted over said second end of the aperture of the permanent magnetic assembly. A source of electrical voltage (which has a first terminal with a first voltage and a second terminal with a second voltage, said second voltage being negative with respect to said first voltage) has its first and second terminals respectively connected to said anode and said cathode to cause an electrostatic field therebetween. In the preferred embodiment the voltage sources are independently variable. In addition, the present device has a means for uniformly passing ionizable gas into the chamber defined by the position of the magnetic flux, the position of the cathodes and the position of the plasma exit plate. Accordingly when electrical energy is applied to the anode and the cathode, a dense plasma results and a substantial amount of the plasma exists above said substantially large aperture to provide a body of plasma external to the device.