RESPONSE OF THE ELECTRON-DENSITY AND TEMPERATURE TO THE POWER INTERRUPTION MEASURED BY THOMSON SCATTERING IN AN INDUCTIVELY-COUPLED PLASMA

Electron density and temperature measurements during a power interruption of the generator are performed on a 100-MHz flowing-argon inductively coupled plasma. The Thomson scattering setup for measuring the density and temperature is triggered in such a way that temperatures and densities are obtained as a function of time while the power is interrupted. The response of the electron temperature to the power interruption shows a jump downwards within 5 mu s, presumably towards the heavy particle temperature. Therefore, the method can be used to determine the heavy particle temperature. Furthermore, insight is obtained as to the behavior of the electron density in the center of the plasma; it increases rather than decreases after the power interruption.