ELECTRON-TEMPERATURE CONTROL FOR PLASMAS PASSING THROUGH A NEGATIVELY BIASED GRID

Electron-temperature control is performed on plasmas passing through a coarse mesh grid from a discharge region. By increasing a negative potential applied to the grid, the electron temperature is continuously decreased in a very wide range covering almost two orders of magnitude down to the value nearly equal to the background gas temperature in case of direct current argon or helium gas discharge. The temperature decrease is accompanied by an increase in the electron density. This method of electron-temperature control can also be applied to plasmas produced by radio-frequency and electron cyclotron resonance discharges.