Quasi-spherical compression of a spark-channel plasma

Abstract

An axial spark channel in deuterium has been used as a target for implosive shock waves created with a conventional cylindrical theta-pinch device. The compression of the channel by the implosive waves raised the plasma electron temperature to ~ 120 eV for ~ 6 kJ of condenser bank energy and 1 Torr initial gas pressure.In order to improve the efficiency of compression, of the channel plasma and to reduce the end losses inherent in the cylindrical configuration, the theta-pinch geometry was then converted from cylindrical into spherical. Under identical conditions of gas pressure and condenser bank energy, the electron temperature now peaked at ~ 400 eV. When the bank energy was increased to ~ 10 kJ, neutron production was observed. The total neutron output per shot ranged from 105 to 106 and increased inversely with the pinch discharge volume.