Spatiotemporal dynamics of drift wave turbulence in a helicon discharge
- MPI for Plasma Physics, EURATOM Association, D-17491 Greifswald (Germany)
This paper presents results of experimental investigations about the spatiotemporal evolution of turbulent structures in weakly developed turbulence in the linearly magnetized helicon discharge VINETA. On the basis of the dispersion behavior the governing instability has been identified as the drift wave instability. A key quantity of drift waves are the associated parallel currents, which are measured with high sensitive B-probes. The fluctuating parallel currents are correlated with the drift wave density fluctuations. Drift waves are driven into a weakly developed turbulent state, which is characterized by strong intermittency of plasma density fluctuations in the far plasma edge. Spatiotemporal measurements revealed that this intermittency can be ascribed to radially propagating turbulent structures, which form in the region of large radial plasma pressure gradient and propagate radially outwards. The radial propagation speeds are typically 10% of the local ion sound speed. Measurements of the parallel electron dynamics associated with the radially propagating structures strongly suggest that the parallel electron flux contributes significantly to the polarization of turbulent structures.
- OSTI ID:
- 21136974
- Journal Information:
- AIP Conference Proceedings, Vol. 993, Issue 1; Conference: PLASMA 2007: International conference on research and applications of plasmas; 4. German-Polish conference on plasma diagnostics for fusion and applications; 6. French-Polish seminar on thermal plasma in space and laboratory, Greifswald (Germany), 16-19 Oct 2007; Other Information: DOI: 10.1063/1.2909181; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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