Density and Temperature Profile Measurement on a Transferred Arc Plasma Using CW Laser Scattering

The electron density and temperature profile of a high-density (1023-m-3, 1.2-eV) transferred arc plasma are obtained with a CW laser scattering technique. Coherent synchronous detection is used to measure the collective scattered light spectra at the thermal level. Local plasma parameters are then inferred from the spectra using the BGK theory modified to account simultaneously for ion-ion as well as ion-neutral collisions in the same model. Those two collisional regimes are clearly identified in the plasma torch. The ability of the model to handle mixed collisional regimes allows a straightforward determination of the local density and temperature independently of position and current level.