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)

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: Bian, Dr Nicolas Horace and Kontar, Professor Eduard and MacKinnon, Dr Alexander
• 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 Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
46593	1	Solar, stellar and cosmological plasmas: a synthesis of data, modelling and theory.	Declan Diver	Science & Technologies Facilities Council (STFC)	ST/F002149/1	Physics and Astronomy