中国物理B ›› 2009, Vol. 18 ›› Issue (5): 2101-.doi: 10.1088/1674-1056/18/5/062

• • 上一篇    

Ion pickup by the intrinsic low-frequency Alfvén waves with a spectrum

李醒1, 董川飞2, 陆全明3   

  1. (1)Institute of Mathematical and Physical Sciences, Aberystwyth University, Aberystwyth, SY23 2BZ, UK; (2)School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China; (3)School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China;State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100080, China
  • 收稿日期:2008-09-22 修回日期:2008-10-19 出版日期:2009-05-20 发布日期:2009-05-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grants Nos 40725013 and 40674093) and Chinese Academy of Sciences (Grant No KJCX2-YW-N28 9140C08060507ZCZJ19).

Ion pickup by the intrinsic low-frequency Alfvén waves with a spectrum

Lu Quan-Ming(陆全明)a)b), Li Xing(李醒)c), and Dong Chuan-Fei(董川飞)a)   

  1. a School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China; b State Key Laboratory of Space Weather, Chinese Academy of Sciences, Beijing 100080, China; c Institute of Mathematical and Physical Sciences, Aberystwyth University, Aberystwyth, SY23 2BZ, UK
  • Received:2008-09-22 Revised:2008-10-19 Online:2009-05-20 Published:2009-05-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grants Nos 40725013 and 40674093) and Chinese Academy of Sciences (Grant No KJCX2-YW-N28 9140C08060507ZCZJ19).

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摘要： Ion pickup by a monochromatic low-frequency Alfvén wave, which propagates along the background magnetic field, has recently been investigated in a low beta plasma (Lu and Li 2007 Phys. Plasmas 14 042303). In this paper, the monochromatic Alfvén wave is generalized to a spectrum of Alfvén waves with random phase. It finds that the process of ion pickup can be divided into two stages. First, ions are picked up in the transverse direction, and then phase difference (randomization) between ions due to their different parallel thermal motions leads to heating of the ions. The heating is dominant in the direction perpendicular to the background magnetic field. The temperatures of the ions at the asymptotic stage do not depend on individual waves in the spectrum, but are determined by the total amplitude of the waves. The effect of the initial ion bulk flow in the parallel direction on the heating is also considered in this paper.

关键词: ion pickup, Alfvén wave, ion heating, temperature anisotropy

Abstract: Ion pickup by a monochromatic low-frequency Alfvén wave, which propagates along the background magnetic field, has recently been investigated in a low beta plasma (Lu and Li 2007 Phys. Plasmas 14 042303). In this paper, the monochromatic Alfvén wave is generalized to a spectrum of Alfvén waves with random phase. It finds that the process of ion pickup can be divided into two stages. First, ions are picked up in the transverse direction, and then phase difference (randomization) between ions due to their different parallel thermal motions leads to heating of the ions. The heating is dominant in the direction perpendicular to the background magnetic field. The temperatures of the ions at the asymptotic stage do not depend on individual waves in the spectrum, but are determined by the total amplitude of the waves. The effect of the initial ion bulk flow in the parallel direction on the heating is also considered in this paper.

Key words: ion pickup, Alfvén wave, ion heating, temperature anisotropy

中图分类号:  (Magnetohydrodynamic waves (e.g., Alfven waves))

  • 52.35.Bj
52.50.-b (Plasma production and heating) 52.65.-y (Plasma simulation)