Negative ion source operation with deuterium

摘要: When the working gas of a negative ion source is changed from hydrogen to its isotope, deuterium, an 'isotope effect' observed; namely, several plasma characteristics such as electron energy distribution, atomic fraction and spectra rovibrationally excited molecules change. The understanding effect becomes more important, research development aiming at ITER power level operation being challenged with feeding deuterium sources. As historical review effort develop hydrogen/deuterium sources, types sources designed for neutral beam heating are described: double charge exchange volume surface-plasma early results operated without cesium introduced. charged compared those hydrogen. isotope did not appear pronounced density was measured in small but became when size enlarged discharge increased higher values. Surface were optimized could achieve same performance pressure. lower velocity ions leaving low work function surface seemed limit production efficiency. Fundamental processes causing these differences summarized. After explaining current status development, acquired knowledge utilized large nuclear fusion compact neutron applications.