Effects of plasma beta on the plasmoid instability

	Effects of plasma beta on the plasmoid instability
	Ni L(倪蕾)1,2 ; Ziegler, U 3; Huang, YM 4; Lin J(林隽)1 ; Mei ZX(梅志星)1
刊名	PHYSICS OF PLASMAS
	2012-07
卷号	19 期号:7
ISSN号	1070-664X
通讯作者	Ni, L (reprint author), Chinese Acad Sci, Yunnan Astron Observ, Kunming 650011, Peoples R China.
产权排序	第一完成单位
英文摘要	The effects of the initial upstream plasma beta on the plasmoid instability are studied via two-dimensional resistive magnetohydrodynamic simulations. For cases with nonuniform beta dependent initial plasma mass density and uniform temperature, our numerical results indicate that the critical Lundquist number for onset of the plasmoid instability depends on the initial plasma beta. The critical Lundquist number is approximately 2000 - 3000 for beta = 50 and is 8000 - 10000 for beta = 0.2. The higher the beta, the smaller the critical Lundquist number is. Similar to previous studies of high-beta systems, the average reconnection rate in low beta systems is found to become weakly dependent on the Lundquist number in the plasmoid-unstable regime. However, the average reconnection rate, normalized to the asymptotic value of upstream BVA, is lower in a low beta system than that in a high beta system. The magnetic energy spectral index, which characterizes fragmentation of the reconnection layer, is approximately two and is insensitive to beta in the high-Lunquist number regime. It is also found that the magnetic reconnection rate becomes similar for different beta cases, if the initial force-balance is provided by temperature gradient instead of density gradient. Therefore, it is concluded that the beta-dependence mentioned above may be largely attributed to the density variation.
学科主题	Physics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Physics, Fluids & Plasmas
研究领域[WOS]	Physics
关键词[WOS]	CURRENT-LAYER FRAGMENTATION ; CURRENT SHEETS ; CASCADING RECONNECTION
收录类别	SCI ; EI
原文出处	http://scitation.aip.org/content/aip/journal/pop/19/7/10.1063/1.4736993
语种	英语
WOS记录号	WOS:000307422800080
内容类型	期刊论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/6198]
专题	云南天文台_太阳物理研究组
作者单位	1.Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming 650011, China 2.Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China 3.Leibniz-Institut für Astrophysik Potsdam, DE 14482 Potsdam, Germany 4.Space Science Center, University of New Hampshire, Durham, New Hampshire 03824, USA
推荐引用方式 GB/T 7714	Ni L,Ziegler, U,Huang, YM,et al. Effects of plasma beta on the plasmoid instability[J]. PHYSICS OF PLASMAS,2012,19(7).
APA	Ni L,Ziegler, U,Huang, YM,Lin J,&Mei ZX.(2012).Effects of plasma beta on the plasmoid instability.PHYSICS OF PLASMAS,19(7).
MLA	Ni L,et al."Effects of plasma beta on the plasmoid instability".PHYSICS OF PLASMAS 19.7(2012).