中国物理B ›› 2021, Vol. 30 ›› Issue (9): 95205-095205.doi: 10.1088/1674-1056/ac0e21

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Numerical investigation of radio-frequency negative hydrogen ion sources by a three-dimensional fluid model

Ying-Jie Wang(王英杰), Jia-Wei Huang(黄佳伟), Quan-Zhi Zhang(张权治), Yu-Ru Zhang(张钰如), Fei Gao(高飞), and You-Nian Wang(王友年)   

  1. Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams(Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, China
  • 收稿日期:2021-05-14 修回日期:2021-06-21 接受日期:2021-06-24 出版日期:2021-08-19 发布日期:2021-09-06
  • 通讯作者: Yu-Ru Zhang, Fei Gao E-mail:yrzhang@dlut.edu.cn;fgao@dlut.edu.cn
  • 基金资助:
    Project supported by the National Key Research and Development Program of China (Grant No. 2017YFE0300106), the National Natural Science Foundation of China (Grant No. 12075049), and the Fundamental Research Funds for the Central Universities, China (Grant Nos. DUT20LAB201 and DUT21LAB110).

Numerical investigation of radio-frequency negative hydrogen ion sources by a three-dimensional fluid model

Ying-Jie Wang(王英杰), Jia-Wei Huang(黄佳伟), Quan-Zhi Zhang(张权治), Yu-Ru Zhang(张钰如), Fei Gao(高飞), and You-Nian Wang(王友年)   

  1. Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams(Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, China
  • Received:2021-05-14 Revised:2021-06-21 Accepted:2021-06-24 Online:2021-08-19 Published:2021-09-06
  • Contact: Yu-Ru Zhang, Fei Gao E-mail:yrzhang@dlut.edu.cn;fgao@dlut.edu.cn
  • Supported by:
    Project supported by the National Key Research and Development Program of China (Grant No. 2017YFE0300106), the National Natural Science Foundation of China (Grant No. 12075049), and the Fundamental Research Funds for the Central Universities, China (Grant Nos. DUT20LAB201 and DUT21LAB110).

摘要: A three-dimensional fluid model is developed to investigate the radio-frequency inductively coupled H2 plasma in a reactor with a rectangular expansion chamber and a cylindrical driver chamber, for neutral beam injection system in CFETR. In this model, the electron effective collision frequency and the ion mobility at high E-fields are employed, for accurate simulation of discharges at low pressures (0.3 Pa-2 Pa) and high powers (40 kW-100 kW). The results indicate that when the high E-field ion mobility is taken into account, the electron density is about four times higher than the value in the low E-field case. In addition, the influences of the magnetic field, pressure and power on the electron density and electron temperature are demonstrated. It is found that the electron density and electron temperature in the xz-plane along permanent magnet side become much more asymmetric when magnetic field enhances. However, the plasma parameters in the yz-plane without permanent magnet side are symmetric no matter the magnetic field is applied or not. Besides, the maximum of the electron density first increases and then decreases with magnetic field, while the electron temperature at the bottom of the expansion region first decreases and then almost keeps constant. As the pressure increases from 0.3 Pa to 2 Pa, the electron density becomes higher, with the maximum moving upwards to the driver region, and the symmetry of the electron temperature in the xz-plane becomes much better. As power increases, the electron density rises, whereas the spatial distribution is similar. It can be summarized that the magnetic field and gas pressure have great influence on the symmetry of the plasma parameters, while the power only has little effect.

关键词: negative hydrogen ion source, inductively coupled plasma, three-dimensional fluid model, magnetic field effect

Abstract: A three-dimensional fluid model is developed to investigate the radio-frequency inductively coupled H2 plasma in a reactor with a rectangular expansion chamber and a cylindrical driver chamber, for neutral beam injection system in CFETR. In this model, the electron effective collision frequency and the ion mobility at high E-fields are employed, for accurate simulation of discharges at low pressures (0.3 Pa-2 Pa) and high powers (40 kW-100 kW). The results indicate that when the high E-field ion mobility is taken into account, the electron density is about four times higher than the value in the low E-field case. In addition, the influences of the magnetic field, pressure and power on the electron density and electron temperature are demonstrated. It is found that the electron density and electron temperature in the xz-plane along permanent magnet side become much more asymmetric when magnetic field enhances. However, the plasma parameters in the yz-plane without permanent magnet side are symmetric no matter the magnetic field is applied or not. Besides, the maximum of the electron density first increases and then decreases with magnetic field, while the electron temperature at the bottom of the expansion region first decreases and then almost keeps constant. As the pressure increases from 0.3 Pa to 2 Pa, the electron density becomes higher, with the maximum moving upwards to the driver region, and the symmetry of the electron temperature in the xz-plane becomes much better. As power increases, the electron density rises, whereas the spatial distribution is similar. It can be summarized that the magnetic field and gas pressure have great influence on the symmetry of the plasma parameters, while the power only has little effect.

Key words: negative hydrogen ion source, inductively coupled plasma, three-dimensional fluid model, magnetic field effect

中图分类号:  (Plasma sources)

  • 52.50.Dg
52.50.Qt (Plasma heating by radio-frequency fields; ICR, ICP, helicons) 52.65.-y (Plasma simulation)