Astron. Astrophys. 348, L29-L32 (1999)

Letter to the Editor

Multi-line two-dimensional spectroscopy of a limb flare

M.D. Ding, C. Fang, S.Y. Yin and P.F. Chen

Nanjing University, Department of Astronomy, Nanjing 210093, P.R. China

Received 2 June 1999 / Accepted 13 July 1999

Abstract

We present the result of a preliminary analysis of the 2D spectra of H and Ca II for a limb flare on 11 November, 1998. Near the top of the flaring loop, the H line is extraordinarily broadened. The effect of line opacity (or the saturation of line core) cannot fully account for the observed line width since it requires an extremely high loop density ( cm^-3 when K). The remaining possibility is the broadening by micro-turbulence or inhomogeneous mass motions. Since the two lines demonstrate different broadening effects, it is quite possible that they are formed in different fine structures which cannot be spatially resolved by observations.

Key words: line: profiles Sun: flares Sun: prominences

Send offprint requests to: M.D. Ding

This article contains no SIMBAD objects.

Contents

• 1. Introduction
• 2. Observations and data reduction
• 3. Line broadening mechanisms
• 4. Conclusion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1999

Online publication: July 26, 1999
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