The effect of Compton scattering on gamma-ray spectra of the 2005 January 20 flare

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	The effect of Compton scattering on gamma-ray spectra of the 2005 January 20 flare
	Chen, Wei; Gan, Wei-Qun
刊名	RESEARCH IN ASTRONOMY AND ASTROPHYSICS
	2012-10-01
卷号	12 期号:10 页码:1439-1450
关键词	Sun: flares Sun: gamma-rays scattering: Compton scattering
ISSN号	1674-4527
英文摘要	Gamma-ray spectroscopy provides a wealth of information about accelerated particles in solar flares, as well as the ambient medium with which these energetic particles interact. The neutron capture line (2.223 MeV), the strongest in the solar gamma-ray spectrum, forms in the deep atmosphere. The energy of these photons can be reduced via Compton scattering. With the fully relativistic GEANT4 toolkit, we have carried out Monte Carlo simulations of the transport of a neutron capture line in solar flares, and applied them to the flare that occurred on 2005 January 20 (X7.1/2B), one of the most powerful gamma-ray flares observed by RHESSI during the 23rd solar cycle. By comparing the fitting results of different models with and without Compton scattering of the neutron capture line, we find that when including the Compton scattering for the neutron capture line, the observed gamma-ray spectrum can be reproduced by a population of accelerated particles with a very hard spectrum (s <= 2.3). The Compton effect of a 2.223 MeV line on the spectra is therefore proven to be significant, which influences the time evolution of the neutron capture line flux as well. The study also suggests that the mean vertical depth for neutron capture in hydrogen for this event is about 8 g cm(-2).
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]	NEUTRON-CAPTURE LINE ; SOLAR-FLARES ; ENERGETIC PARTICLE ; CORONAL ABUNDANCES ; DEEXCITATION LINES ; 28 OCTOBER ; X-RAYS ; EMISSION ; RHESSI ; DISTRIBUTIONS
收录类别	SCI
语种	英语
WOS记录号	WOS:000310476800006
公开日期	2013-01-31
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/8042]
专题	紫金山天文台_太阳高能及相关物理过程研究团组
作者单位	Chinese Acad Sci, Key Lab Dark Matter & Space Astron, Purple Mt Observ, Nanjing 210008, Peoples R China
推荐引用方式 GB/T 7714	Chen, Wei,Gan, Wei-Qun. The effect of Compton scattering on gamma-ray spectra of the 2005 January 20 flare[J]. RESEARCH IN ASTRONOMY AND ASTROPHYSICS,2012,12(10):1439-1450.
APA	Chen, Wei,&Gan, Wei-Qun.(2012).The effect of Compton scattering on gamma-ray spectra of the 2005 January 20 flare.RESEARCH IN ASTRONOMY AND ASTROPHYSICS,12(10),1439-1450.
MLA	Chen, Wei,et al."The effect of Compton scattering on gamma-ray spectra of the 2005 January 20 flare".RESEARCH IN ASTRONOMY AND ASTROPHYSICS 12.10(2012):1439-1450.