%0 Journal Article
%A Cai, J.
%A Liang, Yunfeng
%A Killer, C.
%A Liu, S.
%A Hiller, A.
%A Knieps, A.
%A Schweer, B.
%A Höschen, D.
%A Nicolai, D.
%A Offermanns, G.
%A Satheeswaran, G.
%A Henkel, Marion
%A Hollfeld, K.
%A Grulke, O.
%A Drews, P.
%A Krings, T.
%A Li, Y.
%T A new multi-channel Mach probe measuring the radial ion flow velocity profile in the boundary plasma of the W7-X stellarator
%J Review of scientific instruments
%V 90
%N 3
%@ 1089-7623
%C [S.l.]
%I American Institute of Physics
%M FZJ-2021-01510
%P 033502 -
%D 2019
%X Ion flow velocity measurement in the edge and scraper-off layer region is beneficial to understand the confinement related phenomenon in fusion devices such as impurity transport and plays an important role in impurity control. During the Wendelstein 7-X (W7-X) operation phase 1.2a, a multi-channel (MC) Mach probe mounted on the multi-purpose manipulator has been used to measure radial profiles of edge ion flow velocity. This MC-Mach probe consists of two polar and two radial arrays of directional Langmuir pins (28 pins in total) serving for different aims, of which the polar arrays could obtain a polar distribution of ion saturation current, while the radial arrays can be used to study the dynamic process of a radially propagated event. In this paper, we report the observation of the radially outward propagation of a low frequency mode with a speed of around 200 m/s. The first measurement of the radial ion flow velocity profile using the MC-Mach probe in the boundary plasma of the W7-X with an island divertor will also be presente
%F PUB:(DE-HGF)16
%9 Journal Article
%$ 30927788
%U <Go to ISI:>//WOS:000462917300017
%R 10.1063/1.5054279
%U https://juser.fz-juelich.de/record/891425