Spatially inhomogeneous acceleration of electrons in solar flares

Stackhouse, D. J. and Kontar, E. P. (2018) Spatially inhomogeneous acceleration of electrons in solar flares. Astronomy and Astrophysics, 612, A64. (doi:10.1051/0004-6361/201730708)

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Abstract

The imaging spectroscopy capabilities of the Reuven Ramaty high energy solar spectroscopic imager (RHESSI) enable the examination of the accelerated electron distribution throughout a solar flare region. In particular, it has been revealed that the energisation of these particles takes place over a region of finite size, sometimes resolved by RHESSI observations. In this paper, we present, for the first time, a spatially distributed acceleration model and investigate the role of inhomogeneous acceleration on the observed X-ray emission properties. We have modelled transport explicitly examining scatter-free and diffusive transport within the acceleration region and compare with the analytic leaky-box solution. The results show the importance of including this spatial variation when modelling electron acceleration in solar flares. The presence of an inhomogeneous, extended acceleration region produces a spectral index that is, in most cases, different from the simple leaky-box prediction. In particular, it results in a generally softer spectral index than predicted by the leaky-box solution, for both scatter-free and diffusive transport, and thus should be taken into account when modelling stochastic acceleration in solar flares.

Item Type:Articles
Additional Information:This work was supported by the STFC, via an STFC consolidated grant (EPK) and an STFC studentship (DJS).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Kontar, Dr Eduard and Stackhouse, Mr Duncan
Authors: Stackhouse, D. J., and Kontar, E. P.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Astronomy and Astrophysics
Publisher:EDP Sciences
ISSN:0004-6361
ISSN (Online):1432-0746
Published Online:25 April 2018
Copyright Holders:Copyright © 2018 ESO
First Published:First published in Astronomy and Astrophysics 612: A64
Publisher Policy:Reproduced in accordance with the publisher copyright policy
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