Non-linear Alfvén wave interaction leading to resonant excitation of an acoustic mode in the laboratory

Journal Article · Fri May 15 04:00:00 EDT 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4919275· OSTI ID:22410375

Dorfman, S.; Carter, T. A. ^[1]

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1. Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States)

The nonlinear three-wave interaction process at the heart of the parametric decay process is studied by launching counter-propagating Alfvén waves from antennas placed at either end of the Large Plasma Device [W. Gekelman et al., Rev. Sci. Instrum. 62, 2875 (1991)]. A resonance in the beat wave response produced by the two launched Alfvén waves is observed and is identified as a damped ion acoustic mode based on the measured dispersion relation. Other properties of the interaction including the spatial profile of the beat mode and response amplitude are also consistent with theoretical predictions for a three-wave interaction driven by a nonlinear ponderomotive force. A simple damped, driven oscillator model making use of the MHD equations well-predicts most of the observations, but the width of the resonance curve is still under investigation.

• OSTI ID: 22410375
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 22; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALFVEN WAVES
AMPLITUDES
ANTENNAS
DISPERSION RELATIONS
EXCITATION
INTERACTIONS
MAGNETOHYDRODYNAMICS
NONLINEAR PROBLEMS
OSCILLATORS
PONDEROMOTIVE FORCE
RESONANCE