Diagnosing the source region of a solar burst on 26 September 2011 by using microwave type-III pairs

Tan, B.L., Karlický, M., Mészárosová, H., Kashapova, L., Huang, J., Yan, Y. and Kontar, E.P. (2016) Diagnosing the source region of a solar burst on 26 September 2011 by using microwave type-III pairs. Solar Physics, 291(8), pp. 2407-2418. (doi: 10.1007/s11207-016-0986-y)

Abstract

We report a peculiar and interesting train of microwave Type-III pair bursts in the impulsive rising phase of a solar flare on 26 September 2011. The observations include radio spectrometers at frequencies of 0.80 – 2.00 GHz from the Ondřejov radiospectrograph in the Czech Republic (ORSC), hard X-ray from the Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) and Gamma-Ray Burst Monitor onboard the Fermi Space Telescope (Fermi/GRB), EUV images from the Sun Watcher using APS detectors and image Processing instrument onboard the Project for Onboard Autonomy 2 (SWAP/PROBA2), and magnetograms from the Helioseismic and Magnetic Imager onboard the Solar Dynamic Observatory (SDO/HMI). By using a recently developed method (Tan et al., Res. Astron. Astrophys.16, 82, 2016a), we diagnosed the plasma density, temperature, plasma- ββ , magnetic field near the source region, the energy of energetic electrons, and the distance between the acceleration region and the emission start sites of Type-III bursts. From the diagnostics, we find that i) The plasma density, temperature, magnetic field, and the distance between the acceleration region and the emission start sites have almost no obvious variations during the period of Type-III pair trains, while the energy of electrons has an obvious peak value that is consistent with the hard X-ray emission. ii) The plasma- ββ is much higher than unity, showing a highly dynamic process near the emission start site of Type-III bursts. iii) Although the reversed-slope Type-III branches drift more slowly by one order of magnitude than that of the normal Type-IIIs, the related descending and ascending electrons still could have energy of the same order of magnitude. These facts indicate that both the ascending and descending electrons are possibly accelerated by a similar mechanism and in a small source region. These diagnostics can help us to understand the physics in the source region of solar bursts.

• Item Type: Articles
• Additional Information: This work is supported by the NSFC Grants 11273030, 11373039, 11433006, 11573039, and 2014FY120300, CAS XDB09000000, the Grant P209/12/00103 (GA CR) and Project RVO: 67985815 of the Astronomical Institute AS, as well as by the Marie Curie PIRSES-GA-295272-RADIOSUN project.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Kontar, Professor Eduard
• Authors: Tan, B.L., Karlický, M., Mészárosová, H., Kashapova, L., Huang, J., Yan, Y., and Kontar, E.P.
• 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: 08 September 2016
• Copyright Holders: Copyright © 2016 Springer Science+Business Media
• First Published: First published in Solar Physics 291(8): 2407-2418
• Publisher Policy: Reproduced in accordance with the publisher copyright policy

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