The role of collisionless trapped electron mode turbulence on removal of helium ash and transport of deuterium-tritium ions

Nuclear Fushion

article

Weixin Guo¹  Mingzhu Zhang¹  Lu Wang¹  Ge Zhuang³ 

[1] International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electric and Electronic Engineering, Huazhong University of Science and Technology;School of Physics, Huazhong University of Science and Technology;Department of Engineering and Applied Physics School of Physical Sciences, University of Science and Technology of China

关键词: helium ash removal;    D-T ions;    CTEM turbulence;    isotopic effects;    tokamak plasmas;   

DOI  :  10.1088/1741-4326/abc080

来源: Institute of Physics Publishing Ltd.

【 摘 要 】

Removal of helium ash and the anomalous transport of deuterium (D) and tritium (T) ions driven by collisionless trapped electron mode (CTEM) turbulence in tokamak plasmas with weak magnetic shear are studied. We derive the eigenvalue of CTEM with helium ash, and calculate the quasi-linear turbulent fluxes of helium ash, D and T ions simultaneously. Based on the analytical results, the parametric dependence of CTEM instability as well as the anomalous transport of helium ash and D-T ions is investigated, in order to explore the parameter region that is favorable for expelling more helium ash than D and T ions. It is found that helium ash with higher temperature and steeper density profile plays a role of destabilizing CTEM instability, and has higher transport level than that of T ions. We also find that increasing electron temperature and flattening electron density profile are favorable for exhausting helium ash. Isotopic effects (i.e. increasing the fraction of T ions) enhance the transport of both helium ash and D-T ions. Moreover, the trend of stronger transport level of helium ash than that of D-T ions is enhanced by raising electron temperature and flattening electron density profile as well as isotopic effects. Besides, the diffusivity is much larger than the convection. This indicates that the CTEM turbulence driven helium ash transport is favorable for removing helium ash under the parameter region used in the present paper. The possible relevance of our theoretical results to experimental observations is also discussed.

【 授权许可】

Unknown