On the speed and acceleration of electron beams triggering interplanetary type III radio bursts

Krupar, V., Kontar, E. P. , Soucek, J., Santolik, O., Maksimovic, M. and Kruparova, O. (2015) On the speed and acceleration of electron beams triggering interplanetary type III radio bursts. Astronomy and Astrophysics, 580, A137. (doi: 10.1051/0004-6361/201425308)

Abstract

Aims. Type III radio bursts are intense radio emissions triggered by beams of energetic electrons often associated with solar flares. These exciter beams propagate outwards from the Sun along an open magnetic field line in the corona and in the interplanetary (IP) medium. Methods. We performed a statistical survey of 29 simple and isolated IP type III bursts observed by STEREO/Waves instruments between January 2013 and September 2014. We investigated their time-frequency profiles in order to derive the speed and acceleration of exciter electron beams. Results. We show these beams noticeably decelerate in the IP medium. Obtained speeds range from ~0.02c up to ~0.35c depending on initial assumptions. It corresponds to electron energies between tens of eV and hundreds of keV, and in order to explain the characteristic energies or speeds of type III electrons (~0.1c) observed simultaneously with Langmuir waves at 1 au, the emission of type III bursts near the peak should be predominately at double plasma frequency. Derived properties of electron beams can be used as input parameters for computer simulations of interactions between the beam and the plasma in the IP medium.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Kontar, Professor Eduard
• Authors: Krupar, V., Kontar, E. P., Soucek, J., Santolik, O., Maksimovic, M., and Kruparova, O.
• 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
• Copyright Holders: Copyright © 2015 EDP Sciences
• First Published: First published in Astronomy and Astrophysics 580:A137
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher.

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