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  Fine-scale Explosive Energy Release at Sites of Prospective Magnetic Flux Cancellation in the Core of the Solar Active Region Observed by Hi-C 2.1, IRIS, and SDO

Tiwari, S. K., Panesar, N. K., Moore, R. L., Pontieu, B. D., Winebarger, A. R., Golub, L., et al. (2019). Fine-scale Explosive Energy Release at Sites of Prospective Magnetic Flux Cancellation in the Core of the Solar Active Region Observed by Hi-C 2.1, IRIS, and SDO. Astrophysical Journal, 887(1): 56. doi:10.3847/1538-4357/ab54c1.

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Item Permalink: http://hdl.handle.net/21.11116/0000-0006-6924-C Version Permalink: http://hdl.handle.net/21.11116/0000-0006-6925-B
Genre: Journal Article


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Tiwari, Sanjiv K., Author
Panesar, Navdeep K., Author
Moore, Ronald L., Author
Pontieu, Bart De, Author
Winebarger, Amy R., Author
Golub, Leon, Author
Savage, Sabrina L., Author
Rachmeler, Laurel A., Author
Kobayashi, Ken, Author
Testa, Paola, Author
Warren, Harry P., Author
Brooks, David H., Author
Cirtain, Jonathan W., Author
McKenzie, David E., Author
Morton, Richard J., Author
Peter, Hardi1, Author              
Walsh, Robert W., Author
1Department Sun and Heliosphere, Max Planck Institute for Solar System Research, Max Planck Society, ou_1832289              


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 Abstract: The second Hi-C flight (Hi-C 2.1) provided unprecedentedly high spatial and temporal resolution (~250 km, 4.4 s) coronal EUV images of Fe ix/x emission at 172 Å of AR 12712 on 2018 May 29, during 18:56:21–19:01:56 UT. Three morphologically different types (I: dot-like; II: loop-like; III: surge/jet-like) of fine-scale sudden-brightening events (tiny microflares) are seen within and at the ends of an arch filament system in the core of the AR. Although type Is (not reported before) resemble IRIS bombs (in size, and brightness with respect to surroundings), our dot-like events are apparently much hotter and shorter in span (70 s). We complement the 5 minute duration Hi-C 2.1 data with SDO/HMI magnetograms, SDO/AIA EUV images, and IRIS UV spectra and slit-jaw images to examine, at the sites of these events, brightenings and flows in the transition region and corona and evolution of magnetic flux in the photosphere. Most, if not all, of the events are seated at sites of opposite-polarity magnetic flux convergence (sometimes driven by adjacent flux emergence), implying likely flux cancellation at the microflare's polarity inversion line. In the IRIS spectra and images, we find confirming evidence of field-aligned outflow from brightenings at the ends of loops of the arch filament system. In types I and II the explosion is confined, while in type III the explosion is ejective and drives jet-like outflow. The light curves from Hi-C, AIA, and IRIS peak nearly simultaneously for many of these events, and none of the events display a systematic cooling sequence as seen in typical coronal flares, suggesting that these tiny brightening events have chromospheric/transition region origin.


Language(s): eng - English
 Dates: 2019
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: Peer
 Identifiers: DOI: 10.3847/1538-4357/ab54c1
 Degree: -



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Source 1

Title: Astrophysical Journal
Source Genre: Journal
Publ. Info: Chicago, IL : University of Chicago Press for the American Astronomical Society
Pages: - Volume / Issue: 887 (1) Sequence Number: 56 Start / End Page: - Identifier: ISSN: 0004-637X
CoNE: https://pure.mpg.de/cone/journals/resource/954922828215_2