Investigation of mode coupling in a magnetized plasma column using fast imaging

Journal Article · Tue Mar 15 04:00:00 EDT 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3562876· OSTI ID:21537283

Oldenbuerger, S ^[1]; Brochard, F; Bonhomme, G ^[2]

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1. Itoh Research Center for Plasma Turbulence, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan)
2. Institut Jean Lamour, U.M.R. CNRS 7198, Nancy-Universite, Faculte des Sciences et Techniques, Boulevard des Aiguillettes, BP 70239, F-54506 Vandoeuvre-les-Nancy Cedex (France)

Spectral analysis and bicoherence analysis are applied to fast camera data in order to study the nonlinear mode coupling in the low-{beta} cylindrical magnetized plasma device Mirabelle [T. Pierre et al., Rev. Sci. Instrum. 58, 6 (1987)]. The camera provides a measurement of electron plasma density fluctuations in a complete plasma column cross-section. By extraction of virtual probe data, bicoherence in the frequency domain is obtained and compared to probe signal bicoherence. Two-dimensional camera measurements make it possible to compute the mode number bicoherence as well as the related amplitude weighted phase coherence B*, which conserves time resolution. Investigation of temporal evolution of this quantity and power spectra shows typical sequences where a summed normalized B* peak on a specific mode precedes a gain in spectral energy. The assumption of an energy transfer is confirmed by the value of the phase of B*. In addition to temporal dynamics, bidimensional data make it possible to study the localization of nonlinear couplings. Highest values are detected at a radial position where most of the present modes coexist. Fast camera imaging is a powerful, nonperturbative diagnostic providing two-dimensional time-resolved measurements. An adapted utilization of these data helps to get a better insight in drift wave turbulence and coupling mechanisms.

• OSTI ID: 21537283
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 3 Vol. 18; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CAMERAS
COUPLING
ENERGY TRANSFER
FLUCTUATIONS
NONLINEAR PROBLEMS
PLASMA DENSITY
PLASMA DIAGNOSTICS
THERMONUCLEAR DEVICES
TURBULENCE
VARIATIONS
WAVE PROPAGATION