Derivation of the physical parameters for strong and weak flares from the H_α line

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• 作者：M.A. Semeida ; M.G. Rashed
• 关键词：Solar flares ; Physical parameters ; H-alpha ; Spectral lines
• 刊名：NRIAG Journal of Astronomy and Geophysics
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：5
• 期：1
• 页码：48-54
• 全文大小：870 K

文摘

The two flares of 19 and 30 July 1999 were observed in the H_α line using the multichannel flare spectrograph (MFS) at the Astronomical Institute in Ondřejov, Czech Republic. We use a modified cloud method to fit the H_α line profiles which avoids using the background profile. We obtain the four parameters of the two flares: the source function, the optical thickness at line center, the line-of-sight velocity and the Doppler width. The observed asymmetry profiles have been reproduced by the theoretical ones based on our model. A discussion is made about the results of strong and weak flares using the present method.