Speaker
Gulnara I. Abdullina
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P4.1062.pdf
Properties of Alfvén waves in ohmic plasma in the TUMAN-3M tokamak
G.I. Abdullina, L.G. Askinazi, A.A. Belokurov, V.A. Kornev, S.V. Krikunov, S.V. Lebedev,
D.V. Razumenko, A.I. Smirnov, A.S. Tukachinsky, N.A. Zhubr
Ioffe Institute, St. Petersburg, Russian Federation
The study is devoted to properties of Alfvén waves (AWs) in ohmic plasma in the
TUMAN-3M tokamak [1 – 4]. One of the important parameters of AWs is their location in
the poloidal cross-section of the tokamak plasma. This information is necessary for
identification the type and source of the observed oscillations. The AW location is found to
be in the region r a 0.5 [4], by matching the frequency calculated from electron density
profile to the experimentally measured one. The fact that this region occupies an essential
part of plasma cross-section points to the global nature of the mode. Also, this approximately
corresponds to the region in which q 1 . These characteristics make it possible to identify the
observed mode as GAE (Global Alfvén Eigenmode), and at the same time, exclude the TAE
mode (Toroidal Alfvén Eigenmode). As a result, the distortion of the linear dependence of
AW frequency on AW velocity in [3] is eliminated if the local plasma density values in the
region of AW propagation are used instead of the chord-averaged values for calculation the
AW velocity. Mode structure of AWs, namely poloidal and toroidal mode numbers, was
determined with the in-vessel array of sixteen poloidal fast magnetic probes and two toroidal
ones.
The dependence of AW frequency on increased carbon impurity content has been
studied in deuterium plasma. It is experimentally confirmed that in the case of equal
mass-to-charge ratio for both the main and impurity ions AW frequency is independent of the
impurity density and is determined by the electron plasma density and the main ion mass.
The study of the Alfvén wave location was supported by Russian Science Foundation
(Project # 16-12-10285). The investigation of the Alfvén waves in deuterium plasma with
increased carbon impurity content was supported by Ioffe Institute.
[1] Askinazi L.G. et al 2015 Nucl. Fusion 55 104013
[2] Tukachinsky A.S. et al 2016 Technical Physics Letters 42 pp 1167-1169
[3] Lebedev S.V. et al 2016 Proc. 43rd EPS Conf. on Plasma Phys. P5.036
[4] Abdullina G.I. et al 2018 Technical Physics Letters 44 p 108
