TY  - JOUR
AU  - Liu, S. C.
AU  - Liang, Yunfeng
AU  - Drews, P.
AU  - Krämer-Flecken, A.
AU  - Han, X.
AU  - Nicolai, D.
AU  - Satheeswaran, G.
AU  - Wang, N. C.
AU  - Cai, Jianqing
AU  - Charl, A.
AU  - Cosfeld, J.
AU  - Gao, Yu
AU  - Grulke, O.
AU  - Henkel, M.
AU  - Hollfeld, K. P.
AU  - Killer, C.
AU  - Knieps, A.
AU  - König, R.
AU  - Neubauer, O.
AU  - Rack, M.
AU  - Sandri, N.
AU  - Sereda, S.
AU  - Schweer, B.
AU  - Wang, Erhui
AU  - Wei, Yanling
TI  - Characteristics of the SOL turbulence structure in the first experimental campaign on W7-X with limiter configuration
JO  - Physics of plasmas
VL  - 25
IS  - 7
SN  - 1089-7674
CY  - [S.l.]
PB  - American Institute of Physics
M1  - FZJ-2018-06966
SP  - 072502 -
PY  - 2018
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000440589100037
DO  - DOI:10.1063/1.5033353
UR  - https://juser.fz-juelich.de/record/858022
ER  -