Spectroscopic investigations of electron heating in a high-density helicon discharge

摘要: The evolution of a high-density helicon discharge in argon and argon–helium mixtures was studied by spectroscopic methods as well standard diagnostics. Applying optical emission spectroscopy, the electron temperature deduced from ratio different lines. spectral data were evaluated using collisional-radiative (CR) models taking account secondary processes like transitions between excited levels excitation metastable niveaus. In addition, time-resolved laser absorption spectroscopy applied to determine density Ar*(3P0) atoms profile 772.42 nm line. Due strong coupling collisions, up 1000 K reflects gas ground state atoms. density, which is readily obtained temperature, are needed input parameters for CR models. results compared with Langmuir probe measurements partially utilized passive compensation. main issue this study heating due wave absorption. double radio-frequency (rf) pulse technique variable rf power second pulse, growth measured function power. To clarify whether or not fast electrons generated resonant heating, phase-sensitive Ar II (480 nm) line short lifetime (τ ≈ 7 ns) performed on time-scale (period 73.7 ns). However, no modulation synchronous phase observed. Rather, temporal reveals be predominantly heated bulk energy distribution function.