SECONDARY FAST MAGNETOACOUSTIC WAVES TRAPPED IN RANDOMLY STRUCTURED PLASMAS

doi:10.3847/0004-637X/828/1/17

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	SECONDARY FAST MAGNETOACOUSTIC WAVES TRAPPED IN RANDOMLY STRUCTURED PLASMAS
	Yuan,Ding 1,2; Li,Bo 3; Walsh,Robert W.1
刊名	The Astrophysical Journal
	2016-08-24
卷号	828 期号:1
关键词	magnetohydrodynamics (MHD) methods: numerical Sun: atmosphere Sun: corona Sun: oscillations waves
ISSN号	0004-637X
DOI	10.3847/0004-637X/828/1/17
英文摘要	ABSTRACT Fast magnetoacoustic waves are an important tool for inferring parameters of the solar atmosphere. We numerically simulate the propagation of fast wave pulses in randomly structured plasmas that mimic the highly inhomogeneous solar corona. A network of secondary waves is formed by a series of partial reflections and transmissions. These secondary waves exhibit quasi-periodicities in both time and space. Since the temporal and spatial periods are related simply through the speed of the fast wave, we quantify the properties of secondary waves by examining the dependence of the average temporal period ( ) on the initial pulse width (w0) and studying the density contrast ( ) and correlation length (Lc) that characterize the randomness of the equilibrium density profiles. For small-amplitude pulses, does not alter significantly. Large-amplitude pulses, on the other hand, enhance the density contrast when is small but have a smoothing effect when is sufficiently large. We found that scales linearly with Lc and that the scaling factor is larger for a narrower pulse. However, in terms of the absolute values of , broader pulses generate secondary waves with longer periods, and this effect is stronger in random plasmas with shorter correlation lengths. Secondary waves carry the signatures of both the leading wave pulse and the background plasma. Our study may find applications in magnetohydrodynamic seismology by exploiting the secondary waves detected in the dimming regions after coronal mass ejections or extreme ultraviolet waves.
语种	英语
出版者	The American Astronomical Society
WOS记录号	IOP:0004-637X-828-1-17
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/36346]
专题	中国科学院国家天文台
作者单位	1.Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE, UK; DYuan2@uclan.ac.uk 2.Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012, China 3.Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, 264209 Shandong, China
推荐引用方式 GB/T 7714	Yuan,Ding,Li,Bo,Walsh,Robert W.. SECONDARY FAST MAGNETOACOUSTIC WAVES TRAPPED IN RANDOMLY STRUCTURED PLASMAS[J]. The Astrophysical Journal,2016,828(1).
APA	Yuan,Ding,Li,Bo,&Walsh,Robert W..(2016).SECONDARY FAST MAGNETOACOUSTIC WAVES TRAPPED IN RANDOMLY STRUCTURED PLASMAS.The Astrophysical Journal,828(1).
MLA	Yuan,Ding,et al."SECONDARY FAST MAGNETOACOUSTIC WAVES TRAPPED IN RANDOMLY STRUCTURED PLASMAS".The Astrophysical Journal 828.1(2016).