A possible broadening mechanism of HeI 10 830 angstrom profiles observed in a limb flare

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	A possible broadening mechanism of HeI 10 830 angstrom profiles observed in a limb flare
	Li, H; You, J
刊名	ASTRONOMY & ASTROPHYSICS
	2001-08-01
卷号	374 期号:3 页码:1121-1126
关键词	Sun : flares Sun : infrared line : profiles
ISSN号	1432-0746
英文摘要	The He I 10 830 Angstrom spectra observed in the impulsive phase of the 2N/X20 solar limb are of 16 August 1989 show unusually broad profiles, and most of the profiles are blue-shifted and/or blue asymmetric with full-width-at-half-maximum (FWHM) greater than 10 Angstrom. Contrary to prominences, weak post-flare loops and surges, the observed profiles of the are cannot be simulated by Doppler broadening with a uniform flaring atmosphere model. Calculations show that only when the electron density is greater than 10(16) cm(-3) can Stark broadening produce an obvious in fence on the He I 10 830 Angstrom profile. This indicates that it is not plausible that Stark broadening leads to the observed profiles even though they can be fitted by Stark broadening. Alternatively, an expanding flaring atmosphere can perfectly simulate all the observed He I 10 830 Angstrom profiles. The expanding velocities are generally several tens of km s(-1) and that corresponding to the widest profile is greater than 120 km s(-1). Expanding velocity and other parameters vary with time and the observed area. This expanding flaring atmosphere model is a perspective candidate for line broadening. It is an indication of the lateral expansion resulting from rapid chromospheric heating in addition to the upward evaporation and downward condensation.
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]	CHROMOSPHERIC EVAPORATION ; IMPULSIVE PHASE ; SOLAR-FLARES ; SPECTRA ; BEAM
收录类别	SCI
语种	英语
WOS记录号	WOS:000170215900035
公开日期	2013-01-31
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/8195]
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	Acad Sinica, Purple Mt Observ, Natl Astron Observ, Nanjing 210008, Peoples R China
推荐引用方式 GB/T 7714	Li, H,You, J. A possible broadening mechanism of HeI 10 830 angstrom profiles observed in a limb flare[J]. ASTRONOMY & ASTROPHYSICS,2001,374(3):1121-1126.
APA	Li, H,&You, J.(2001).A possible broadening mechanism of HeI 10 830 angstrom profiles observed in a limb flare.ASTRONOMY & ASTROPHYSICS,374(3),1121-1126.
MLA	Li, H,et al."A possible broadening mechanism of HeI 10 830 angstrom profiles observed in a limb flare".ASTRONOMY & ASTROPHYSICS 374.3(2001):1121-1126.