Theoretical investigation of the onsets of type II radio bursts during solar eruptions

	Theoretical investigation of the onsets of type II radio bursts during solar eruptions
	Lin J(林隽)1 ; Mancuso, S 2; Vourlidas, A 3
刊名	ASTROPHYSICAL JOURNAL
	2006-10-01
卷号	649 期号:2 页码:1110-1123
关键词	Sun : coronal mass ejections (CMEs) Sun : flares Sun : magnetic fields Sun : radio radiation
ISSN号	0004-637X
通讯作者	Lin, J (reprint author), Chinese Acad Sci, Yunnan Astron Observ, Natl Astron Observ China, POB 110, Kunming 650011, Yunnan, Peoples R China.
产权排序	第一完成单位
英文摘要	On the basis of previous works, we investigated coronal mass ejection (CME) propagations and the consequent type II radio bursts invoked by the CME-driven shocks. The results indicate that the onset of type II bursts depends on the local Alfven speed (or the magnetoacoustic wave speed in the non-force-free environment), which is governed by both the magnetic field and the plasma density. This determines that the type II burst cannot appear at any altitude. Instead, its onset positions can never be lower than a critical height for the given coronal environment, which consequently determines the start frequencies of the emission: for an eruption taking place in the magnetic configuration with a background field of 100 G, the onset of type II bursts should occur at around 0.5 R(circle dot) from the solar surface, and the corresponding start frequency of the fundamental component is about 150 MHz. This result is consistent with similar estimates based on observations that bring the corresponding frequency to a few hundred MHz. Our results further indicate that the onset of type II bursts depends on the rate of magnetic reconnection as well. When magnetic reconnection during the eruption is not fast enough, a type II burst may not occur at all even if the associated CME is fast ( say, faster than 800 km s(-1)). This may account for the fast and radio-quiet CMEs. Related to these results, properties of the associated solar flares and type III radio bursts, especially those used as the precursors of the type II radio bursts, are also discussed.
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	CORONAL MASS EJECTIONS ; RECONNECTING CURRENT SHEETS ; RAY FLARE EMISSION ; MAGNETIC RECONNECTION ; FLUX-ROPE ; CHROMOSPHERIC EVAPORATION ; PARTICLE-ACCELERATION ; HEATING MECHANISMS ; LIGHT CURVES ; SHOCK-WAVES
收录类别	SCI
原文出处	http://iopscience.iop.org/0004-637X/649/2/1110/
语种	英语
WOS记录号	WOS:000240854200050
公开日期	2016-05-03
内容类型	期刊论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/6086]
专题	云南天文台_太阳物理研究组
作者单位	1.National Astronomical Observatories of China/Yunnan Astronomical Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming, Yunnan 650011, China; and Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 2.INAF/Osservatorio Astronomico di Torino, 20 Strada Osservatorio, I-10025 Pino Torinese, Italy 3.Solar Physics Branch, Naval Research Laboratory, 4555 Overlook Avenue, SW, Washington, DC 20375
推荐引用方式 GB/T 7714	Lin J,Mancuso, S,Vourlidas, A. Theoretical investigation of the onsets of type II radio bursts during solar eruptions[J]. ASTROPHYSICAL JOURNAL,2006,649(2):1110-1123.
APA	Lin J,Mancuso, S,&Vourlidas, A.(2006).Theoretical investigation of the onsets of type II radio bursts during solar eruptions.ASTROPHYSICAL JOURNAL,649(2),1110-1123.
MLA	Lin J,et al."Theoretical investigation of the onsets of type II radio bursts during solar eruptions".ASTROPHYSICAL JOURNAL 649.2(2006):1110-1123.