Electric field profiles around an electrical probe immersed in a plasma
- Sandia National Laboratories, Albuquerque, New Mexico 87185-1423 (United States)
Laser-induced fluorescence-dip spectroscopy was used to measure the spatial distribution of electric fields around a biased cylindrical probe in an argon rf discharge. Two-dimensional maps of the field profiles were obtained around the probe as functions of argon pressure, discharge power, probe bias, and phase of the rf cycle. Analysis of the radial dependence of the electric fields indicated that the ion density decreased in the vicinity of the probe for all cases, contrary to the orbit motion limited regime typically employed for Langmuir probe analysis. We also observed perturbation of the plasma by the presence of the probe that extended many times the measurable length scale of the sheath ({approx}5{delta}x{sub sheath}) into the plasma around the probe. Electric field distributions were also measured as functions of distance from the plasma sheath boundary. Coupling between the bounding sheath fields of the plasma and those formed around the biased probe was observed, even at distances greater than length scales of either sheath.
- OSTI ID:
- 20884962
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 1 Vol. 101; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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