Thermal insulation of the target plasma in the open-quotes Ambal-Yuclose quotes mirror device

When open magnetic confinement systems are filled with a target plasma through the mirror it is possible in principle to obtain a thermal barrier between the gas-discharge source and the target plasma it produces in the mirror device. Without using auxiliary heating systems (hf power, neutral beams, magnetic compression) a hot target plasma with density ∼ 3 · 1013 cm-3 and electron temperature greater than 50 eV has been produced in the open-quotes Ambal-Yuclose quotes mirror device from a quasisteady plasma source with a low temperature ∼ 10 eV. The ions reach a high temperature (Ti/Te much-gt 1) because they undergo heating in the Kelvin-Helmholtz instability. When a particular magnetic field topology is used in the system the electron component that has been heated by the ions is observed to be thermally insulated from the plasma source. The measured density, potential, and plasma temperature profiles confirm that there is a thermal barrier localized in the entry mirror of the confinement system. 9 refs., 8 figs