Speaker
Peng Shi
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P1.1088.pdf
Experimental observations of ITG and TEM instabilities on J-TEXT
tokamak
P. Shi1, G. Zhuang1,2*, J. Chen3, Y.N. Zhou1
1
International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma
Physics, Huazhong University of Science and Technology, Wuhan 430074, China
2
School of Physical Sciences, University of Science and Technology of China,
Hefei, Anhui 230026, China
3
Department of Physics and Astronomy, University of California Los Angeles, Los Angeles,
California 90095, USA
Recently, two different quasi-coherent (QC) density fluctuations have been measured by the
newly developed far-forward collective scattering measurements on J-TEXT tokamak Ohmic
plasmas. The two QC instabilities have characteristic frequencies in the range of 30 − 100𝑘𝐻
(low-frequency) and 150 − 250𝑘𝐻𝑧 (high-frequency) respectively. And the corresponding
characteristic normalized wavenumber is estimated to be in the range of 𝑘𝜃 𝜌𝑠 < 0.1 and
0.15 < 𝑘𝜃 𝜌𝑠 < 0.3 respectively. Furthermore, the propagation directions in plasma frame for
the low-frequency (LF) and high-frequency (HF) QC instabilities are identified to be ion and
electron diamagnetic direction respectively. Considering the features of the two QC modes and
the discharge conditions on J-TEXT, the LF and HF QC modes are predicted to be the
ion-temperature-gradient (ITG) driven instability and the trapped electron mode (TEM)
respectively. In addition, the variations of ITG and TEM modes during density ramp-up have
been investigated. More details will be showed in the poster.
