Speaker
Jianqing Cai
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P1.1020.pdf
Measurements of the radial ion flow velocity profile using the multi-
channel Mach probe in the boundary plasma of the W7-X stellarator
J. Cai1,3, Y. Liang1, S. Liu1,3, P. Drews1, C. Killer2, A. Knieps1, Y. Li1,3, M. Henkel1, D.
Nicolai1, G. Satheeswaran1, Daniel Höschen1, A. Hiller1 and the W7-X Team
1
Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung–
Plasmaphysik , 52425 Jülich,
2
Max-Planck-Institut für Plasmaphysik, Greifswald, Germany Germany
3
Institute of Plasma Physics, Chinese Academy of Sciences, PO Box 1126, Hefei
230031, People's Republic of China
Ion flow velocity measurement in the edge and scraper-off layer (SOL) is important to
understand the edge physics in fusion devices for the aims of impurity control and
advanced confinement. During the Wendelstein 7-X (W7-X) experimental campaign
OP1.2a [1, 2], the multi-channel (MC) Mach probe mounted on the multi-purpose
manipulator (MPM) [3] has been used to measure the radial profiles of ion flow velocity
as well as the electron density and temperature profile. 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 are used to study the dynamic process of
radially propagated event. Besides, a sweeping voltage from -200V to 200V is applied
to one of the Mach probe pins, by which the electron density and temperature profile
could be obtained. In this paper, the first measurement of radial ion flow velocity profile
using the MC-Mach probe in the boundary plasma of W7-X with island divertor will
be presented. The impacts of magnetic topology on the edge ion flow will be discussed.
Reference
[1] Y Liang, O Neubauer, et al., Nuclear Fusion 57 (6), 066049, (2017)
[2] RC Wolf, A Ali, A Alonso, et al., Nuclear Fusion 57 (10), 102020, (2017)
[3] D Nicolai, V Borsuk, P Drews, Y Liang, et al., Fusion Engineering and Design 123, 960-964, (2017)
