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A magnetically insulated diode has been used to produce intense fluxes of protons with high efficiency. Currents in excess of 4 kA with current density greater than 50 A/cm2 have been produced in a 50-nsec bursts at energies up to 200 keV. The system appears to be easily scalable to higher parameters. The extraction of the beams, as well as geometries in which current densities of kA/cm2 may be realized, are discussed.

The theoretically favorable plasma-confinement properties of field-reversed magnetic field configurations have led to many reactor proposals. 1 " 5 Such configurations have been experimentally realized (i) by the injection of relativistic electron beams 6 to form a reversed-field electron ring, 7 (ii) by plasma currents induced by relativistic-electron-beam injection, 8 and (ill) by reversed-field 0 pinches. 9 However, synchrotron-radiation energy losses make a relativistic electron ring unsuitable for a fusion reactor. Indeed, Christofilos amended his original Astron concept 1 by replacing electrons with high-energy protons. Developments in intense-ion-beam 10 " 13 technology make it possible for a reversed-field ion ring to be produced by single-pulse injection. 2 This has led to two experimental programs 12 * 13 aimed at the injection and trapping of an ion ring in a mirror magnetic field.In this Letter, we report experimental results on the production and propagation of a rotating beam of the type required for ion-ring formation.

As part of the program to develop a large-area thin-film pulse heater for a lithium ion source, the residual stress in post cathode magnetron sputter deposited molybdenum films has been studied. It was found that in films prepared in the low-pressure sputtering regime, the residual film stress is very sensitive to the gas pressure during sputtering and that the film stresses are highly anisotropic. The transition pressure for changing from compressive to tensile residual stress, as defined by Thornton and Hoffman, depends on the relationship between the measurement direction in the film and the post cathode orientation. In order to deposit a nearly stress-free film a pressure cycling technique was developed which deposited alternate film layers containing tensile and compressive stresses. Film resistivity and thermal coefficient of resistivity measurements were made during the pulse heating of the molybdenum films.