Ion and neutral temperatures in an electron cyclotron resonance plasma

Transverse ion and neutral temperatures at the electron cyclotron resonance position were measured in an electron cyclotron resonance (ECR) plasma usi ng a high-resolution optical emission spectroscopy of Doppler profiles of A r and Ar+ transition. The transverse ion temperature increase from approxim ately 0.4 to 1.0 eV as the operating gas pressure is lowered from 1.0 to 0. 1 mTorr. On the other hand, the transverse neutral temperature is much lowe r than the transverse ion temperature. By means of Langmuir probe measureme nt, large-amplitude potential fluctuation was observed at the ECR position under the low gas pressure. These observations suggest that the large-ampli tude potential fluctuation directly affects the transverse ion temperature. (C) 2001 Elsevier Science B.V. All rights reserved.