中国物理B ›› 2022, Vol. 31 ›› Issue (7): 75201-075201.doi: 10.1088/1674-1056/ac5883

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Modeling of beam ions loss and slowing down with Coulomb collisions in EAST

Yifeng Zheng(郑艺峰)1, Jianyuan Xiao(肖建元)1,†, Baolong Hao(郝保龙)2, Liqing Xu(徐立清)3, Yanpeng Wang(王彦鹏)1, Jiangshan Zheng(郑江山)1, and Ge Zhuang(庄革)1   

  1. 1 School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026, China;
    2 Key Laboratory of Optoelectronic Devices and Systems, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China;
    3 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
  • 收稿日期:2021-12-24 修回日期:2022-02-07 接受日期:2022-02-25 出版日期:2022-06-09 发布日期:2022-07-19
  • 通讯作者: Jianyuan Xiao E-mail:xiaojy@ustc.edu.cn
  • 基金资助:
    Project supported by the National MCF Energy Research and Development Program (Grant No. 2018YFE0304100), the National Key Research and Development Program of China (Grant Nos. 2016YFA0400600, 2016YFA0400601, 2016YFA0400602, 2019YFE03020004, and 2019YFE03040004), and the National Natural Science Foundation of China (Grant Nos. 11805273 and 11905220). One of the authors (Yifeng Zheng) thanks Feng Wang and Shijie Liu from Dalian University of Technology for the benchmark work with PTC. Numerical computations were performed on Tianhe High Performance Computing Cluster in National Supercomputer Center in Tianjin.

Modeling of beam ions loss and slowing down with Coulomb collisions in EAST

Yifeng Zheng(郑艺峰)1, Jianyuan Xiao(肖建元)1,†, Baolong Hao(郝保龙)2, Liqing Xu(徐立清)3, Yanpeng Wang(王彦鹏)1, Jiangshan Zheng(郑江山)1, and Ge Zhuang(庄革)1   

  1. 1 School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026, China;
    2 Key Laboratory of Optoelectronic Devices and Systems, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China;
    3 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
  • Received:2021-12-24 Revised:2022-02-07 Accepted:2022-02-25 Online:2022-06-09 Published:2022-07-19
  • Contact: Jianyuan Xiao E-mail:xiaojy@ustc.edu.cn
  • Supported by:
    Project supported by the National MCF Energy Research and Development Program (Grant No. 2018YFE0304100), the National Key Research and Development Program of China (Grant Nos. 2016YFA0400600, 2016YFA0400601, 2016YFA0400602, 2019YFE03020004, and 2019YFE03040004), and the National Natural Science Foundation of China (Grant Nos. 11805273 and 11905220). One of the authors (Yifeng Zheng) thanks Feng Wang and Shijie Liu from Dalian University of Technology for the benchmark work with PTC. Numerical computations were performed on Tianhe High Performance Computing Cluster in National Supercomputer Center in Tianjin.

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摘要： This paper uses the implicit Monte-Carlo full-orbit-following parallel program ISSDE to calculate the prompt loss and slowing down process of neutral beam injection (NBI)-generated fast ions due to Coulomb collisions in the equilibrium configuration of Experimental Advanced Superconducting Tokamak (EAST). This program is based on the weak equivalence of the Fokker-Planck equation under Rosenbluth MacDonald Judd (RMJ) potential and Stratonovich stochastic differential equation (SDE). The prompt loss with the LCFS boundary and the first wall (FW) boundary of the two co-current neutral injection beams are studied. Simulation results indicate that the loss behavior of fast ions using the FW boundary is very different from that of the LCFS boundary, especially for fast ions with a large gyration radius. According to our calculations, about 5.11% of fast ions generated by perpendicular injection drift out of the LCFS and then return inside the LCFS to be captured by the magnetic field. The prompt loss ratio of fast ions and the ratio of orbital types depend on the initial distribution of fast ions in the Pζ-$\varLambda$ space. Under the effect of Coulomb collisions, the pitch-angle scattering and stochastic diffusion happens, which will cause more fast ion loss. For short time scales, among the particles lost due to collisions, the fraction of banana ions reaches 92.31% in the perpendicular beam and 58.65% in the tangential beam when the fraction of banana ions in the tangential beam is 3.4% of the total ions, which means that the effect of Coulomb collisions on banana fast ions is more significant. For long time scales, the additional fast ion loss caused by Coulomb collisions of tangential and perpendicular beams accounted for 16.21% and 25.05% of the total particles, respectively. We have also investigated the slowing down process of NBI fast ions.

关键词: NBI fast ion loss, slowing down process, EAST, Coulomb collisions

Abstract: This paper uses the implicit Monte-Carlo full-orbit-following parallel program ISSDE to calculate the prompt loss and slowing down process of neutral beam injection (NBI)-generated fast ions due to Coulomb collisions in the equilibrium configuration of Experimental Advanced Superconducting Tokamak (EAST). This program is based on the weak equivalence of the Fokker-Planck equation under Rosenbluth MacDonald Judd (RMJ) potential and Stratonovich stochastic differential equation (SDE). The prompt loss with the LCFS boundary and the first wall (FW) boundary of the two co-current neutral injection beams are studied. Simulation results indicate that the loss behavior of fast ions using the FW boundary is very different from that of the LCFS boundary, especially for fast ions with a large gyration radius. According to our calculations, about 5.11% of fast ions generated by perpendicular injection drift out of the LCFS and then return inside the LCFS to be captured by the magnetic field. The prompt loss ratio of fast ions and the ratio of orbital types depend on the initial distribution of fast ions in the Pζ-$\varLambda$ space. Under the effect of Coulomb collisions, the pitch-angle scattering and stochastic diffusion happens, which will cause more fast ion loss. For short time scales, among the particles lost due to collisions, the fraction of banana ions reaches 92.31% in the perpendicular beam and 58.65% in the tangential beam when the fraction of banana ions in the tangential beam is 3.4% of the total ions, which means that the effect of Coulomb collisions on banana fast ions is more significant. For long time scales, the additional fast ion loss caused by Coulomb collisions of tangential and perpendicular beams accounted for 16.21% and 25.05% of the total particles, respectively. We have also investigated the slowing down process of NBI fast ions.

Key words: NBI fast ion loss, slowing down process, EAST, Coulomb collisions

中图分类号:  (Electron collisions)

  • 52.20.Fs
52.25.Xz (Magnetized plasmas) 52.40.Mj (Particle beam interactions in plasmas) 52.50.Gj (Plasma heating by particle beams)