Unique Point on Langmuir Probe Characteristics under Influence of Potential Fluctuations
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A unique point is observed on Langmuir probe characteristics when sinusoidal potential fluctuations with frequencies less than ion plasma frequency are applied. When a direct current (DC) voltage is applied to the probe, current does not change at different sinusoidal radio frequency fluctuation amplitudes. The difference between the DC voltage at this point and that at a point in plasma space is approximately one-half the electron temperature. To analyze this point, Monte Carlo simulations are performed. It is found that an ion density peak appears near the sheath edge when the positive probe potential decreases and it propagates toward the plasma when the probe potential is negative. It is concluded that this peak may be related to the plasma oscillation at the sheath edge and may govern the electron flow toward the probe.
- Jpn J Appl Phys
Jpn J Appl Phys 45(10B), 8137-8140, 2006-10-30
INSTITUTE OF PURE AND APPLIED PHYSICS