Speaker
Xiaolan Zou
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.1081.pdf
Turbulence Regulation with Radial Wavenumber Spectral Shift Caused by
LHCD Induced Velocity Shear during ELM Mitigation
X.L. Zou1, G.L. Xiao2,3, W.L. Zhong2, S.D. Song2, X.R. Duan2, A.D. Liu4, X.Y. Bai2,
J. Cheng2, Z.Y. Cui2, L. Delpech1, X.T. Ding2, J.Q. Dong2,5, A. Ekedahl1, B.B. Feng2,
G. Giruzzi1, J.M. Gao2, M. Goniche1, G.T. Hoang1, X.Q. Ji2, M. Jiang2, B. Lu2, D. Mazon1,
Y. Peysson1, X.M. Song2, Z.B. Shi2, M. Xu2, D.L.Yu2, B.Y. Zhang2, Y.P. Zhang2, Y. Zhou2
and HL-2A team2
1
CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
2
Southwestern Institute of Physics, P.O. Box 432, Chengdu, China
3
Department of Engineering physics, Tsinghua University, Beijing, China
4
KTX Laboratory and Department of Modern Physics, University of Science and Technology of
China, Anhui Hefei 230026,China
5
Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou, China
Email: xiao-lan.zou@cea.fr
ELM mitigation with LHCD has been achieved in the HL-2A tokamak for high plasma
density (ne ≥ 2.5×1019 m-3) and large LHCD absorbed power (PLHCD ≥ 300 kW) [1]. The
divertor peak heat load induced by ELM has been significantly reduced during the mitigation
phase. A severe decrease of the pedestal velocity shear has been observed with LHCD switch
on, while the kr-spectrum of the pedestal turbulence is shifted toward the origin (Fig.1(d)). It
has been found that the ELM mitigation is desynchronized with LHCD pulse, but it is closely
correlated to the pedestal turbulence enhancement (Fig.1(e)).
In order to understand the mechanism of the turbulence
enhancement during ELM mitigation, a theoretical
model, based on the regulation of the turbulence
amplitude by its radial wavenumber spectral shift caused
by external velocity shear, has been developed. A critical
growth rate for the turbulence regulation has been
identified in this model. It has been found that the
turbulence enhancement and ELM mitigation occur
Fig.1 ELM mitigation with LHCD.
when the decrease of LHCD driven velocity shear
exceeds a threshold value, which directly depends on . Good agreement has been found
between experiment and theory for the regulation of the turbulence amplitude with its
averaged radial wavenumber.
Reference
[1] G.L. Xiao et al., Phys. Plasmas 24 (2017) 122507
