%0 Journal Article
%A Liu, S. C.
%A Liang, Yunfeng
%A Drews, P.
%A Krämer-Flecken, A.
%A Han, X.
%A Nicolai, D.
%A Satheeswaran, G.
%A Wang, N. C.
%A Cai, Jianqing
%A Charl, A.
%A Cosfeld, J.
%A Gao, Yu
%A Grulke, O.
%A Henkel, M.
%A Hollfeld, K. P.
%A Killer, C.
%A Knieps, A.
%A König, R.
%A Neubauer, O.
%A Rack, M.
%A Sandri, N.
%A Sereda, S.
%A Schweer, B.
%A Wang, Erhui
%A Wei, Yanling
%T Characteristics of the SOL turbulence structure in the first experimental campaign on W7-X with limiter configuration
%J Physics of plasmas
%V 25
%N 7
%@ 1089-7674
%C [S.l.]
%I American Institute of Physics
%M FZJ-2018-06966
%P 072502 -
%D 2018
%X 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.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000440589100037
%R 10.1063/1.5033353
%U https://juser.fz-juelich.de/record/858022