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Quasi-periodic radio bursts associated with fast-mode waves near a magnetic null point
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Kumar, Pankaj, Nakariakov, V. M. (Valery M.) and Cho, Kyung-Suk (2017) Quasi-periodic radio bursts associated with fast-mode waves near a magnetic null point. The Astrophysical Journal, 844 (2). 149. doi:10.3847/1538-4357/aa7d53 ISSN 0004-637X.
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WRAP-quasi-periodic-radio-fast-mode-waves-null-point-Nakariakov-2017.pdf - Accepted Version - Requires a PDF viewer. Download (23Mb) | Preview |
Official URL: http://dx.doi.org/10.3847/1538-4357/aa7d53
Abstract
This paper presents an observation of quasi-periodic rapidly propagating waves observed in the Atmospheric Image Assembly (AIA) 171/193 Å channels during the impulsive phase of an M1.9 flare that occurred on 2012 May 7. The instant period was found to decrease from 240 to 120 s, and the speed of the wavefronts was in the range of ~664–1416 km s−1. Almost simultaneously, quasi-periodic bursts with similar instant periods, ~70 and ~140 s, occur in the microwave emission and in decimetric type IV and type III radio bursts, and in the soft X-ray emission. The magnetic field configuration of the flare site was consistent with a breakout topology, i.e., a quadrupolar field along with a magnetic null point. The quasi-periodic rapidly propagating wavefronts of the EUV emission are interpreted as a fast magnetoacoustic wave train. The observations suggest that the fast-mode waves are generated during the quasi-periodic magnetic reconnection in the cusp region above the flare arcade loops. For the first time, we provide evidence of a tadpole wavelet signature at about 70–140 s in decimetric (245/610 MHz) radio bursts, along with the direct observation of a coronal fast-mode wave train in EUV. In addition, at AIA 131/193 Å we observed quasi-periodic EUV disturbances with periods of 95 and 240 s propagating downward at apparent speeds of 172–273 km s−1. The nature of these downward propagating disturbances is not revealed, but they could be connected to magnetoacoustic waves or periodically shrinking loops.
Item Type: | Journal Article | |||||||||||||||||||||
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Subjects: | Q Science > QB Astronomy Q Science > QC Physics |
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Divisions: | Faculty of Science, Engineering and Medicine > Science > Physics | |||||||||||||||||||||
Library of Congress Subject Headings (LCSH): | Solar flares, Sun -- Corona, Solar oscillations, Solar radiation, Solar radio bursts | |||||||||||||||||||||
Journal or Publication Title: | The Astrophysical Journal | |||||||||||||||||||||
Publisher: | Institute of Physics Publishing, Inc. | |||||||||||||||||||||
ISSN: | 0004-637X | |||||||||||||||||||||
Official Date: | 2 August 2017 | |||||||||||||||||||||
Dates: |
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Volume: | 844 | |||||||||||||||||||||
Number: | 2 | |||||||||||||||||||||
Article Number: | 149 | |||||||||||||||||||||
DOI: | 10.3847/1538-4357/aa7d53 | |||||||||||||||||||||
Status: | Peer Reviewed | |||||||||||||||||||||
Publication Status: | Published | |||||||||||||||||||||
Access rights to Published version: | Restricted or Subscription Access | |||||||||||||||||||||
Date of first compliant deposit: | 17 January 2018 | |||||||||||||||||||||
Date of first compliant Open Access: | 18 January 2018 | |||||||||||||||||||||
RIOXX Funder/Project Grant: |
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Is Part Of: | European Research Council under the SeismoSun Research Project No. 321141 0000-0001-6423-8286 |
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