TY - JOUR
T1 - Signatures of Magnetic Reconnection at the Footpoints of Fan-shaped Jets on a Light Bridge Driven by Photospheric Convective Motions
AU - Bai, Xianyong
AU - Socas-Navarro, Hector
AU - Nóbrega-Siverio, Daniel
AU - Su, Jiangtao
AU - Deng, Yuanyong
AU - Li, Dong
AU - Cao, Wenda
AU - Ji, Kaifan
N1 - Funding Information:
We thank the BBSO’s observing and engineering staff for support and observations. The BBSO operation is supported by NJIT and an NSF AGS-1821294 grant. The GST operation is partly supported by the Korea Astronomy and Space Science Institute and Seoul National University and by the strategic priority research program of the Chinese Academy of Science (CAS) with grant XDB09000000. We acknowledge the free data usage policy of the SDO. IRIS is a NASA small explorer mission developed and operated by LMSAL with mission operations executed at NASA Ames Research Center and major contributions to downlink communications funded by ESA and the Norwegian Space Centre. We also thank the Community Spectropolarimetric Analysis Center for providing the HINODE/SP data. This research work is supported by grants 11873062, 11427901, 11427803, 11773072, 11773038, 11773040, 11703042, U1731241, 11573012, 11673038, XDA15010800, XDB09040200, and U.S. NSF AGS-1821294. The work is also supported by a Young Researcher Grant from the National Astronomical Observatories, Chinese Academy of Sciences. This research work is supported by grant No. 11873062, 11427901, 11427803, 11773072, 11773038, 11773040, 11703042, U1731241, 11573012, 11673038, XDA15010800, XDB09040200, U.S. NSF AGS-1821294 and by a Young Researcher Grant from the National Astronomical Observatories, Chinese Academy of Sciences. This research was also supported by the Research Council of Norway through its Centres of Excellence scheme, project No. 262622, and through grants of computing time from the Programme for Supercomputing.
Publisher Copyright:
© 2019. The American Astronomical Society.
PY - 2019/1/10
Y1 - 2019/1/10
N2 - Dynamical jets are generally found on light bridges (LBs), which are key to studying sunspot decay. So far, their formation mechanism is not fully understood. In this paper, we used state-of-the-art observations from the Goode Solar Telescope, the Interface Region Imaging Spectrograph, the Spectro-polarimeter on board Hinode, and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory to analyze the fan-shaped jets on LBs in detail. A continuous upward motion of the jets in the ascending phase is found from the Hα velocity that lasts for 12 minutes and is associated with the Hα line wing enhancements. Two mini jets appear on the bright fronts of the fan-shaped jets visible in the AIA 171 and 193 A channels, with a time interval as short as 1 minute. Two kinds of small-scale convective motions are identified in the photospheric images, along with the Hα line wing enhancements. One seems to be associated with the formation of a new convection cell, and the other manifests as the motion of a dark lane passing through the convection cell. The finding of three-lobe Stokes V profiles and their inversion with the NICOLE code indicate that there are magnetic field lines with opposite polarities in LBs. From the Hα -0.8 A images, we found ribbon-like brightenings propagating along the LBs, possibly indicating slipping reconnection. Our observation supports the idea that the fan-shaped jets under study are caused by magnetic reconnection, and photospheric convective motions play an important role in triggering the magnetic reconnection.
AB - Dynamical jets are generally found on light bridges (LBs), which are key to studying sunspot decay. So far, their formation mechanism is not fully understood. In this paper, we used state-of-the-art observations from the Goode Solar Telescope, the Interface Region Imaging Spectrograph, the Spectro-polarimeter on board Hinode, and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory to analyze the fan-shaped jets on LBs in detail. A continuous upward motion of the jets in the ascending phase is found from the Hα velocity that lasts for 12 minutes and is associated with the Hα line wing enhancements. Two mini jets appear on the bright fronts of the fan-shaped jets visible in the AIA 171 and 193 A channels, with a time interval as short as 1 minute. Two kinds of small-scale convective motions are identified in the photospheric images, along with the Hα line wing enhancements. One seems to be associated with the formation of a new convection cell, and the other manifests as the motion of a dark lane passing through the convection cell. The finding of three-lobe Stokes V profiles and their inversion with the NICOLE code indicate that there are magnetic field lines with opposite polarities in LBs. From the Hα -0.8 A images, we found ribbon-like brightenings propagating along the LBs, possibly indicating slipping reconnection. Our observation supports the idea that the fan-shaped jets under study are caused by magnetic reconnection, and photospheric convective motions play an important role in triggering the magnetic reconnection.
KW - Sun: activity
KW - Sun: atmosphere
KW - Sun: magnetic fields
KW - methods: observational
KW - sunspots
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U2 - 10.3847/1538-4357/aaf1d1
DO - 10.3847/1538-4357/aaf1d1
M3 - Article
AN - SCOPUS:85060190858
SN - 0004-637X
VL - 870
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 90
ER -