51. Mechanism of VHF H2 plasma production at high pressures
- Author
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Yoshinobu Kawai, Yu Jer Tsai, Kuo Feng Chiu, Kiichiro Uchino, Ting Kuei Lien, Kuan Chen Chen, Chia-Fu Chen, Cheng Yang Lien, and Kohei Ogiwara
- Subjects
010302 applied physics ,Plasma parameters ,Chemistry ,General Engineering ,General Physics and Astronomy ,02 engineering and technology ,Electron ,Plasma ,021001 nanoscience & nanotechnology ,01 natural sciences ,Ion ,symbols.namesake ,0103 physical sciences ,Electrode ,symbols ,Langmuir probe ,Atomic physics ,0210 nano-technology ,Electron distribution - Abstract
A VHF H2 plasma was produced by a narrow-gap discharge at high pressures, and the plasma parameters were examined with the Langmuir probe. A bi-Maxwellian electron distribution was observed near the discharge electrode at a discharge gap of 10 mm, while a Maxwellian distribution was seen near the center. When the discharge gap was 15 mm, electrons had a Maxwellian distribution independent of the position. It was found that there must be a threshold in the discharge gap for stochastic heating to occur. The plasma potential near the discharge electrode was higher than that near the center of the interelectrode gap, suggesting the existence of negative ions. The simulation using the plasma hybrid code was carried out. The spatial profiles of the density and temperature of electrons were similar to the experimental results. The plasma potential had a hill-like profile that was quite different from the measured one. The negative ion density was negligible.
- Published
- 2016
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