Spectroscopic Observations of Magnetic Reconnection and Chromospheric Evaporation in an X-shaped Solar Flare

Journal Article · Fri Oct 20 04:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA89E4· OSTI ID:22679746

Li, Y.; Gan, W. Q. ^[1]; Kelly, M.; Qiu, J. ^[2]; Ding, M. D. ^[3]; Zhu, X. S. ^[4]

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1. Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)
2. Department of Physics, Montana State University, Bozeman, MT 59717 (United States)
3. School of Astronomy and Space Science, Nanjing University, Nanjing 210023 (China)
4. CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Beijing 100012 (China)

We present observations of distinct UV spectral properties at different locations during an atypical X-shaped flare (SOL2014-11-09T15:32) observed by the Interface Region Imaging Spectrograph ( IRIS ). In this flare, four chromospheric ribbons appear and converge at an X-point where a separator is anchored. Above the X-point, two sets of non-coplanar coronal loops approach laterally and reconnect at the separator. The IRIS slit was located close to the X-point, cutting across some of the flare ribbons and loops. Near the location of the separator, the Si iv 1402.77 Å line exhibits significantly broadened line wings extending to 200 km s{sup −1} with an unshifted line core. These spectral features suggest the presence of bidirectional flows possibly related to the separator reconnection. While at the flare ribbons, the hot Fe xxi 1354.08 Å line shows blueshifts and the cool Si iv 1402.77 Å, C ii 1335.71 Å, and Mg ii 2803.52 Å lines show evident redshifts up to a velocity of 80 km s{sup −1}, which are consistent with the scenario of chromospheric evaporation/condensation.

• OSTI ID: 22679746
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 848; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CHROMOSPHERE
INTERFACES
MAGNETIC RECONNECTION
RED SHIFT
SOLAR FLARES
SUN
ULTRAVIOLET RADIATION
VELOCITY