Abstract: In the present device the lower section is an external plasma gun which acts as a source of ionized gas. The upper section of the device is a magnetron which has a plasma chamber and which includes both a source of magnetic flux as well as the apparatus necessary to generate an electrostatic field so that within the plasma chamber of the magnetron there are EXB forces. The magnetron is supported in close proximity to, and is electrically insulated from, the external plasma gun. The above arrangement permits the magnetron to produce and maintain a plasma phenomenon with a very low pressure of gas (of the order of one millitorr to two tenths of a millitorr) in the vacuum chamber.

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.