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arXiv 1608.04823physics.space-ph
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利用Alfvenic涨落耗散对ICME内等离子体加热的研究

Plasma heating inside ICMEs by Alfvenic fluctuations dissipation

Hui Li, Chi Wang, Jiansen He, Lingqian Zhang, John D. Richardson, John W. Belcher, Cui Tu

摘要:

在行星际日冕物质抛射(ICME)的非绝热膨胀过程中,低频阿尔文涨落(AF)的非线性级联被认为是加热等离子体的一种候选能源。然而,ICME内的AF在文献中很少报道。在这项研究中,我们调查AF ICME内使用旅行者2号1和6 AU之间的观测。结果表明,在所有的ICME中,几乎所有的ICME(33个ICME中的30个),以及12.6%的ICME时间间隔内,都有高Alfvenity程度的AF发生。当ICME扩张并向外移动时,AF持续时间的百分比通常线性衰减。ICME内AF的出现率远低于环境太阳风,特别是在4au以内。ICME内部的AF更频繁地出现在ICME的中心和边界处。此外,ICME内部的质子温度也有类似的分布。这些发现表明,AF对ICME内局部等离子体加热的重要贡献。

英文摘要:

Nonlinear cascade of low-frequency Alfvenic fluctuations (AFs) is regarded as one candidate of the energy sources to heat plasma during the non-adiabatic expansion of interplanetary coronal mass ejections (ICMEs). However, AFs inside ICMEs were seldom reported in the literature. In this study, we investigate AFs inside ICMEs using observations from Voyager 2 between 1 and 6 au. It is found that AFs with high degree of Alfvenicity frequently occurred inside ICMEs, for almost all the identified ICMEs (30 out of 33 ICMEs), and 12.6% of ICME time interval. As ICMEs expand and move outward, the percentage of AF duration decays linearly in general. The occurrence rate of AFs inside ICMEs is much less than that in ambient solar wind, especially within 4 au. AFs inside ICMEs are more frequently presented in the center and at the boundaries of ICMEs. In addition, the proton temperature inside ICME has a similar distribution. These findings suggest significant contribution of AFs on local plasma heating inside ICMEs.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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