A COMPARATIVE-STUDY OF THE ELECTRON-DISTRIBUTION FUNCTION IN THE POSITIVE COLUMNS IN N-2 AND N-2 HE DC GLOW-DISCHARGES BY OPTICAL SPECTROSCOPY AND PROBES/

We compare to the probe method a spectroscopic method for determining in plasmas the electron distribution function (EDF) over a wide energy range. For a test of the radiative-collisional model we use to descri be the plasma radiation, the measured vibrational distributions of N-2 (C-B) and N-2(+)(B-X) were compared with calculated ones using our mod el and EDFs measured by Langmuir probes. From this comparison we obtai n a value for the rate constant for vibrational relaxation at the wall s. In a second step we invert the system of model equations for obtain ing the EDF from measured line intensities. From the vibrational struc ture of the emission spectra of the nitrogen molecule the EDF is obtai ned in the energy range of 1.5-4.5 eV. From the relative intensities o f the emission of nitrogen molecules and helium atoms the EDF for elec tron energies above 11 eV is derived. In the region between these rang es the EDF is interpolated. The results agree within the limits of the experimental errors with the EDF measured directly by the probe.