Electron temperature in a  -pinch determined from impurity line radiation

The time variation of the electron temperature during the early compression of a θ-pinch has been determined from the times of appearance and peak intensity of lines of carbon and oxygen in their various stages of ionization. By numerically integrating the rate of ionization equations for specified time variations of electron density and temperature, one can predict the transient behaviour of various lines. The temperature-time dependence is then adjusted until agreement with experiment is obtained. This procedure gives the temperature to within similar 50 per cent when it is varying rapidly, and the electron is known within a factor of two. The results from the carbon and oxygen data are in agreement. With no initial magnetic field, 0.010 mm D 2 , and peak field of 42 kG at 6.7 μsec, the time behaviour of the electron temperature was found to be 5, 50, 120 and 200-300 eV, at respectively 0.5, 1.0, 1.5 and 2.0 μsec. These electron temperatures are significantly lower than the best estimates of the deuteron energies at corresponding times.