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- Title
Diagnostics of thermal and non-thermal processes in solar flares using chromospheric lines.
- Authors
Ding, M. D.; Cheng, J. X.; Li, J. P.
- Abstract
The non-thermal electrons accelerated during solar flares can produce enhanced and broadened chromospheric lines when they precipitate into the chromosphere. In this paper, we propose a method to diagnose the non-thermal processes using two chromospheric lines, ${H\alpha}$ and Ca ${\sc ii} 8542 \AA}$ lines. First, we perform non-LTE calculations of these two lines for various (thermal) model atmospheres and (non-thermal) electron beams. Since the two lines have different sensitivities to the non-thermal electrons, a set of line spectra can uniquely determine a model atmosphere and an electron beam. We then apply this method to a solar flare for which we have observed two-dimensional spectra of the two lines. In particular, we examine the temporal variation of thermal vs. non-thermal effects in flare bright kernels, as well as the spatial variation across flare ribbons. The results show clearly that the non-thermal effects appear most obviously at the flare maximum, and preferentially at the outer edges of flare ribbons. The results are consistent with flare theoretical models.
- Publication
Proceedings of the International Astronomical Union, 2006, Vol 2, Issue S233, p397
- ISSN
1743-9213
- Publication type
Article
- DOI
10.1017/S1743921306002316