Determination of Temperature in a Toroidal Theta Pinch Discharge with an Image Converter Camera
With an image converter camera, developed at the Instituut voor Plasma-Fysica, streak pictures have been made of toroidal θ-pinch discharges in helium at pressures ranging from 0.01 to 0.06 torr. The discharges are produced by a capacitor bank of 2.5 kJ. From the pictures the acceleration of the outward drifting plasma column and the drift time (1 to 2 μs) have been measured. From these quantities the mean plasma temperature after the compression has been determined. The temperature depends on the pressure and varies from about 5 x 105°K at 0.01 torr to 105°K at 0.06 torr. These results are compared with temperatures calculated from the irreversible heating during the compression. From spectroscopical measurements of the intensities of He II λ = 4686 Å and He I λ = 5015 Å the electron temperature is estimated and the assumption of complete ionization is checked.