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Correlation analysis of waves above a capacitive plasma applicator.
W Gekelman1, M Barnes, S Vincena
1Department of Physics and Astronomy, University of California, Los Angeles, California, USA.
Physical Review Letters
|August 8, 2009
Summary
Researchers discovered normal modes in electric potential within capacitive plasma discharges, similar to sound waves in membranes. This finding, observed using advanced spectral analysis, reveals new insights into plasma behavior for materials processing.
Area of Science:
- Physics
- Plasma Science
- Materials Science
Background:
- Capacitively coupled plasma glow discharges are vital for industrial materials processing.
- Research has focused on plasma sheaths and standing waves in capacitive applicators.
Purpose of the Study:
- To demonstrate the existence of normal modes in electric potential within capacitive plasma discharges.
- To characterize these modes and their behavior.
Main Methods:
- Utilized cross spectral analysis of plasma potential measurements.
- Collected data at 208 spatial positions with 1 GHz sampling frequency using an emissive probe.
Main Results:
- Demonstrated, for the first time, normal modes in electric potential analogous to vibrational modes.
- Observed these modes at multiple frequencies, described by Bessel functions.
- Evidence suggests nonlinear interactions between modes of different frequencies.
Conclusions:
- Normal modes exist in the electric potential of capacitive plasma discharges.
- These modes exhibit characteristics similar to physical wave phenomena.
- Further research into nonlinear mode interactions is warranted.
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