| Line Broadening in a Limb Flare：Derivation of Macro—turbulent Velocity Fields |
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| 引用本文： | YingLiu Ming－DeDing.Line Broadening in a Limb Flare：Derivation of Macro—turbulent Velocity Fields[J].中国天文和天体物理学报,2002,2(3):277-286. |
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| 作者姓名： | YingLiu Ming－DeDing |
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| 作者单位： | Ying Liu and Ming-De DingDepartment of Astronomy，Nanjing University，Nanjing 210093 |
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| 基金项目： | 国家自然科学基金，国家重点基础研究发展计划(973计划)，TRAPOYT |
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| 摘 要： | The line profiles of Hα in a limb flare on 1998 November 11 appear to be unusually broadened. It is considered that macro-turbulence (or macroscopic mass motions) may be one of the main causes. We use an inversion technique to extract the probability distribution of the line-of-sight velocity in the flare. There exist some differences between the velocity distributions deduced from Hα and from CaⅡ λ8542, which may be because the two lines depend differently on the temperature and velocity. Since the loop density is high, we obtain a rather short cooling time (several tens of seconds) from the hot X-ray loops to the cool loops visible in Hα. Possible origins of the large scale motions are discussed.
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| 关 键 词： | 太阳 耀斑 大气动力学 X射线 湍流速度 |
Line Broadening in a Limb Flare: Derivation of Macro-turbulent Velocity Fields |
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| Ying Liu,Ming-De Ding.Line Broadening in a Limb Flare: Derivation of Macro-turbulent Velocity Fields[J].Chinese Journal of Astronomy and Astrophysics,2002,2(3):277-286. |
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| Authors: | Ying Liu Ming-De Ding |
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| Institution: | DepartmentofAstronomy,NanjingUniversity,Nanjing210093 |
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| Abstract: | The line profiles of Hα in a limb flare on 1998 November 11 appear to beunusually broadened. It is considered that macro-turbulence (or macroscopic massmotions) may be one of the main causes. We use an inversion technique to extractthe probability distribution of the line-of-sight velocity in the flare. There existsome differences between the velocity distributions deduced from Hα and from Ca IIλ8542, which may be because the two lines depend differently on the temperatureand velocity. Since the loop density is high, we obtain a rather short cooling time(several tens of seconds) from the hot X-ray loops to the cool loops visible in Hα.Possible origins of the large scale motions are discussed. |
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| Keywords: | Sun: flares - Sun: atmospheric motions - Line: profiles |
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