STUDY OF THE EXPANSION OF A PLASMA GENERATED BY ELECTRON-BEAM EVAPORATION

The stationary expansion of an ionized uranium vapor, created in an el ectron-beam evaporator, is studied in this article. Using an electrost atic probe, the electron temperature, the electron density, and the pl asma potential have been measured along the vertical axis in the evapo rator. The analysis, made by moving the probe along the vertical axis, first shows that the plasma is thermalized during its expansion in th e vacuum chamber and, second, that the plasma density decreases expone ntially. The plasma expansion is theoretically described using a fluid model which takes into account the charge exchange process. In solvin g the system, consisting of three equations (continuity, momentum cons ervation, and energy conservation!, good agreement with the experiment al data is obtained. (C) 1998 American Institute of Physics. [S0021-89 79(98)09020-3].