Turbulent cross-field transport of non-thermal electrons in coronal loops: theory and observations

Bian, N.H., Kontar, E.P. and MacKinnon, A.L. (2011) Turbulent cross-field transport of non-thermal electrons in coronal loops: theory and observations. Astronomy and Astrophysics, 535(A18), (doi:10.1051/0004-6361/201117574)

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Abstract

<p><b>Context:</b> A fundamental problem in astrophysics is the interaction between magnetic turbulence and charged particles. It is now possible to use Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observations of hard X-rays (HXR) emitted by electrons to identify the presence of turbulence and to estimate the magnitude of the magnetic field line diffusion coefficient at least in dense coronal flaring loops.</p> <p><b>Aims:</b> We discuss the various possible regimes of cross-field transport of non-thermal electrons resulting from broadband magnetic turbulence in coronal loops. The importance of the Kubo number K as a governing parameter is emphasized and results applicable in both the large and small Kubo number limits are collected.</p> <p><b>Methods:</b> Generic models, based on concepts and insights developed in the statistical theory of transport, are applied to the coronal loops and to the interpretation of hard X-ray imaging data in solar flares. The role of trapping effects, which become important in the non-linear regime of transport, is taken into account in the interpretation of the data.</p> <p><b>Results:</b> For this flaring solar loop, we constrain the ranges of parallel and perpendicular correlation lengths of turbulent magnetic fields and possible Kubo numbers. We show that a substantial amount of magnetic fluctuations with energy ~1% (or more) of the background field can be inferred from the measurements of the magnetic diffusion coefficient inside thick-target coronal loops.</p>

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:MacKinnon, Dr Alexander and Kontar, Dr Eduard and Bian, Dr Nicolas Horace
Authors: Bian, N.H., Kontar, E.P., and MacKinnon, A.L.
College/School:College of Science and Engineering > School of Physics and Astronomy
College of Social Sciences > School of Education > Interdisciplinary Science Education Technologies and Learning
Journal Name:Astronomy and Astrophysics
Publisher:EDP Sciences
ISSN:0004-6361
ISSN (Online):1432-0746
Copyright Holders:Copyright © 2011 EDP Sciences
First Published:First published in Astronomy and Astrophysics 535(A18)
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
465931Solar, stellar and cosmological plasmas: a synthesis of data, modelling and theory.Declan DiverScience & Technologies Facilities Council (STFC)ST/F002149/1Physics and Astronomy