Impulsively Generated Wave Trains in Coronal Structures. I. Effects of Transverse Structuring on Sausage Waves in Pressureless Tubes

	Impulsively Generated Wave Trains in Coronal Structures. I. Effects of Transverse Structuring on Sausage Waves in Pressureless Tubes
	Yu, Hui; Li, Bo; Chen, Shao-Xia; Xiong, Ming; Guo, Ming-Zhe
刊名	ASTROPHYSICAL JOURNAL
	2017
卷号	836 期号:1 页码:1
关键词	magnetohydrodynamics (MHD) Sun: corona Sun: flares Sun: magnetic fields waves
ISSN号	0004-637X
英文摘要	The behavior of the axial group speeds of trapped sausage modes plays an important role in determining impulsively generated wave trains, which have often been invoked to account for quasi-periodic signals with quasi-periods of the. order of seconds in a considerable number of coronal structures. We conduct a comprehensive eigenmode analysis, both analytically and numerically, on the dispersive properties of sausage modes in pressureless tubes with three families of continuous radial density profiles. We find a rich variety of the dependence on the axial wavenumber k of the axial group speed v(gr). Depending on the density contrast and profile steepness as well as on the detailed profile description, the v(gr)-k curves either possess or do not possess cutoff wavenumbers, and they can behave in either a monotonical or non-monotonical manner. With time-dependent simulations, we further show that this rich variety of the group speed characteristics heavily influences the temporal evolution and Morlet spectra of impulsively generated wave trains. In particular, the Morlet spectra can look substantially different from the "crazy tadpoles" found for the much-studied discontinuous density profiles. We conclude that it is necessary to re-examine available high-cadence data to look for the rich set of temporal and spectral features that can be employed to discriminate between the unknown forms of the density distributions transverse to coronal structures.
收录类别	SCI
语种	英语
内容类型	期刊论文
源URL	[http://ir.nssc.ac.cn/handle/122/5815]
专题	国家空间科学中心_空间科学部
推荐引用方式 GB/T 7714	Yu, Hui,Li, Bo,Chen, Shao-Xia,et al. Impulsively Generated Wave Trains in Coronal Structures. I. Effects of Transverse Structuring on Sausage Waves in Pressureless Tubes[J]. ASTROPHYSICAL JOURNAL,2017,836(1):1.
APA	Yu, Hui,Li, Bo,Chen, Shao-Xia,Xiong, Ming,&Guo, Ming-Zhe.(2017).Impulsively Generated Wave Trains in Coronal Structures. I. Effects of Transverse Structuring on Sausage Waves in Pressureless Tubes.ASTROPHYSICAL JOURNAL,836(1),1.
MLA	Yu, Hui,et al."Impulsively Generated Wave Trains in Coronal Structures. I. Effects of Transverse Structuring on Sausage Waves in Pressureless Tubes".ASTROPHYSICAL JOURNAL 836.1(2017):1.