Solar plasma radio emission in the presence of imbalanced turbulence of kinetic-scale Alfvén waves

Lyubchyk, O., Kontar, E.P. , Voitenko, Y.M., Bian, N.H. and Melrose, D.B. (2017) Solar plasma radio emission in the presence of imbalanced turbulence of kinetic-scale Alfvén waves. Solar Physics, 292(9), 117. (doi:10.1007/s11207-017-1140-1)

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Abstract

We study the influence of kinetic-scale Alfvénic turbulence on the generation of plasma radio emission in the solar coronal regions where the ratio ββ of plasma to magnetic pressure is lower than the electron-to-ion mass ratio me/mime/mi . The present study is motivated by the phenomenon of solar type I radio storms that are associated with the strong magnetic field of active regions. The measured brightness temperature of the type I storms can be up to 1010 K1010 K for continuum emission, and can exceed 1011 K1011 K for type I bursts. At present, there is no generally accepted theory explaining such high brightness temperatures and some other properties of the type I storms. We propose a model with an imbalanced turbulence of kinetic-scale Alfvén waves that produce an asymmetric quasi-linear plateau on the upper half of the electron velocity distribution. The Landau damping of resonant Langmuir waves is suppressed and their amplitudes grow spontaneously above the thermal level. The estimated saturation level of Langmuir waves is high enough to generate observed type I radio emission at the fundamental plasma frequency. Harmonic emission does not appear in our model because the backward-propagating Langmuir waves undergo strong Landau damping. Our model predicts 100%100% polarization in the sense of the ordinary (o-) mode of type I emission.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Kontar, Dr Eduard and Bian, Dr Nicolas Horace
Authors: Lyubchyk, O., Kontar, E.P., Voitenko, Y.M., Bian, N.H., and Melrose, D.B.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Solar Physics
Publisher:Springer
ISSN:0038-0938
ISSN (Online):1573-093X
Published Online:16 August 2017
Copyright Holders:Copyright © 2017 The Authors Springer Science+Business Media B.V
First Published:First published in Solar Physics 292(9):117
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
631581Consolidated grant in solar and astrophysical plasmasLyndsay FletcherScience & Technology Facilities Council (STFC)ST/L000741/1S&E P&A - PHYSICS & ASTRONOMY