Battaglia, M., Fletcher, L. and Simões, P. J. A. (2014) Where is the chromospheric response to conductive energy input from a hot pre-flare coronal loop? Astrophysical Journal, 789(1), p. 47. (doi: 10.1088/0004-637X/789/1/47)
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Abstract
Before the onset of a flare is observed in hard X-rays there is often a pro- longed pre-flare or pre-heating phase with no detectable hard X-ray emission but pronounced soft X-ray emission suggesting that energy is being released and deposited into the corona and chromosphere already at this stage. This work analyses the temporal evolution of coronal source heating and the chromospheric response during this pre-heating phase to investigate the origin and nature of early energy release and transport during a solar flare. Simultaneous X-ray, EUV, and microwave observations of a well observed flare with a prolonged pre-heating phase are analysed to study the time evolution of the thermal emission and to determine the onset of particle acceleration. During the 20 minutes duration of the pre-heating phase we find no hint of accelerated electrons, neither in hard X-rays nor in microwave emission. However, the total energy budget during the pre-heating phase suggests that energy must be supplied to the flaring loop to sustain the observed temperature and emission measure. Under the assumption of this energy being transported toward the chromosphere via thermal conduc- tion, significant energy deposition at the chromosphere is expected. However, no detectable increase of the emission in the AIA wavelength channels sensitive to chromospheric temperatures is observed. The observations suggest energy release and deposition in the flaring loop before the onset of particle acceleration, yet a model in which energy is conducted to the chromosphere and subsequent heating of the chromosphere is not supported by the observations.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Simoes, Dr Paulo and Fletcher, Professor Lyndsay and Battaglia, Dr Marina |
| Authors: | Battaglia, M., Fletcher, L., and Simões, P. J. A. |
| Subjects: | Q Science > QB Astronomy Q Science > QC Physics |
| College/School: | College of Science and Engineering > School of Physics and Astronomy |
| Research Group: | Astronomy and Astrophysics |
| Journal Name: | Astrophysical Journal |
| Journal Abbr.: | ApJ |
| Publisher: | American Astronomical Society |
| ISSN: | 0004-637X |
| ISSN (Online): | 1538-4357 |
| Copyright Holders: | Copyright © 2014 The American Astronomical Society |
| First Published: | First published in Astrophysical Journal 789(1):47 |
| Publisher Policy: | Reproduced in accordance with the copyright policy of the publisher |
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