Characteristics of the SOL turbulence structure in the first experimental campaign on W7-X with limiter configuration
Year: 2018
Type: article
Abstract: In the first experimental campaign of Wendelstein 7-X (W7-X), a combined probe head mounted on the multi-purpose manipulator has been used to measure the scrape-off layer (SOL) turbulence characteristics. The preliminary experimental results are summarized to illustrate the SOL turbulence properties in the limiter configuration on W7-X. In a standard limiter configuration, significant electrostatic fluctuations can be found in the near SOL, and the dominant frequency of fluctuation power is below 100 kHz. The auto-correlation spectrum power law decay factor is α ≈ −1 below 40 kHz and α ≈ –2 between 50 and 200 kHz. A broadband spectrum appears between 240 and 380 kHz with a low spectral power density, but a high cross-correlation coefficient. The statistical characteristics of turbulence are calculated by the two-point cross-correlation technique. A clear poloidal dispersion relation is found in the spectrum S(kθ, f), propagating along the ion diamagnetic drift direction with a group velocity (below 100 kHz) about 0.56 km/s in the near SOL in the laboratory frame. The poloidal correlation length is around 5–10 mm in SOL. The turbulence phase velocity is about 0.5–1 km/s when close to the last closed flux surface, which is comparable with the poloidal E × B drift speed.
Source: Physics of Plasmas
DOI: 10.1063/1.5033353
Authors: S. C. Liu, Y. Liang, P. Drews, A. Krämer-Flecken, X. Han, D. Nicolai, G. Satheeswaran, N. C. Wang, J. Q. Cai, A. Charl, J. Cosfeld, Y. Gao, O. Grulke, M. Henkel, K. P. Hollfeld, C. Killer, A. Knieps, R. König, O. Neubauer, M. Rack, N. Sandri, S. Sereda, B. Schweer, E. H. Wang, Y. L. Wei, W7-X Team
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium, G2731829129, G2808143221, G2902593495, G3510875179, Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium, G6177046699, G829439530, G858011915
OpenAlex ID: W2810724709