The plasmascope-a new opto-electronic method for velocity measurements in thermal plasmas

A new opto-electronic instrument for linear velocity measurements in plasmas has been developed. It incorporates a linear photodiode array and measures the intensity profiles of light emitted by a plasma section. Velocities are determined from the shift of intensity variations (typical error: 10%). Velocities of NaCl powder injected into a thermal induction plasma and of the plasma gas itself were measured and the scatter of the results is explained. The advantages of this method are immediate display of the results, versatility and the possibility of on-line data treatment.