Low Altitude Solar Magnetic Reconnection, Type III Solar Radio Bursts, and X-ray Emissions

I. H. Cairns, V. V. Lobzin, A. Donea, S. J. Tingay, P. I. McCauley, D. Oberoi, R. T. Duffin, M. J. Reiner, N. Hurley-Walker, N. A. Kudryavtseva, D. B. Melrose, J. C. Harding, G. Bernardi, J. D. Bowman, R. J. Cappallo, B. E. Corey, A. Deshpande, D. Emrich, R. Goeke, B. J. HazeltonM. Johnston-Hollitt, D. L. Kaplan, J. C. Kasper, E. Kratzenberg, C. J. Lonsdale, M. J. Lynch, S. R. McWhirter, D. A. Mitchell, M. F. Morales, E. Morgan, S. M. Ord, T. Prabu, A. Roshi, N. Udaya Shankar, K. S. Srivani, R. Subrahmanyan, R. B. Wayth, M. Waterson, R. L. Webster, A. R. Whitney, A. Williams, C. L. Williams

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Type III solar radio bursts are the Sun's most intense and frequent nonthermal radio emissions. They involve two critical problems in astrophysics, plasma physics, and space physics: how collective processes produce nonthermal radiation and how magnetic reconnection occurs and changes magnetic energy into kinetic energy. Here magnetic reconnection events are identified definitively in Solar Dynamics Observatory UV-EUV data, with strong upward and downward pairs of jets, current sheets, and cusp-like geometries on top of time-varying magnetic loops, and strong outflows along pairs of open magnetic field lines. Type III bursts imaged by the Murchison Widefield Array and detected by the Learmonth radiospectrograph and STEREO B spacecraft are demonstrated to be in very good temporal and spatial coincidence with specific reconnection events and with bursts of X-rays detected by the RHESSI spacecraft. The reconnection sites are low, near heights of 5-10 Mm. These images and event timings provide the long-desired direct evidence that semi-relativistic electrons energized in magnetic reconnection regions produce type III radio bursts. Not all the observed reconnection events produce X-ray events or coronal or interplanetary type III bursts; thus different special conditions exist for electrons leaving reconnection regions to produce observable radio, EUV, UV, and X-ray bursts.

Original languageEnglish
Article number1676
Number of pages12
JournalScientific Reports
Issue number1
Publication statusPublished - 1 Dec 2018

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Cairns, I. H., Lobzin, V. V., Donea, A., Tingay, S. J., McCauley, P. I., Oberoi, D., Duffin, R. T., Reiner, M. J., Hurley-Walker, N., Kudryavtseva, N. A., Melrose, D. B., Harding, J. C., Bernardi, G., Bowman, J. D., Cappallo, R. J., Corey, B. E., Deshpande, A., Emrich, D., Goeke, R., ... Williams, C. L. (2018). Low Altitude Solar Magnetic Reconnection, Type III Solar Radio Bursts, and X-ray Emissions. Scientific Reports, 8(1), [1676]. https://doi.org/10.1038/s41598-018-19195-3