Ion and Neutral Temperatures in a Novel Ultrahigh-Frequency Discharge Plasma

Ion and neutral temperatures are measured in an ultrahigh-frequency discharge plasma through Ar and Ne by Doppler-shifted laser-induced fluorescence. The ion and neutral temperatures are estimated to be ≈0.066 eV (770 K) for Ar+ and 0.033±0.004 eV ( 380 ±50 K) for Ne, respectively. These temperatures are lower than those reported for electron cyclotron resonance and helicon wave plasmas. The low temperatures are attributed to the low electron temperature ( ≈2 eV) and excellent uniformity of the UHF plasma.