Electron-temperature and spontaneous-magnetic-field measurements in a laser-irradiated free jet

Abstract
The output of a Q‐switched ruby laser irradiated a freely expanding jet of nitrogen gas. The laser optical axis was collinear with that of the jet. Gaseous breakdown occurred and the remaining energy within the laser pulse heated the plasma and drove forward‐travelling waves through the orifice and into the plenum of the jet. The temperature of the electrons within the plasma was measured using relative transmittance of x rays through thin metal‐foil spectrometers. The temperature varied as the square of the wave velocity from 60 to 160 eV. Measurements were also made of the spontaneous magnetic field generated in the vicinity of the plasma.