CONFINED FLARES IN SOLAR ACTIVE REGION 12192 FROM 2014 OCTOBER 18 TO 29

Journal Article · Mon Jul 20 04:00:00 EDT 2015 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/808/1/L24· OSTI ID:22518927

Chen, Huadong; Zhang, Jun; Yang, Shuhong; Li, Leping; Huang, Xin; Xiao, Junmin ^[1]; Ma, Suli ^[2]

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1. Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)
2. College of Science, China University of Petroleum, Qingdao 266580 (China)

Using the observations from the Atmospheric Imaging Assembly and Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory, we investigate 6 X-class and 29 M-class flares occurring in solar active region (AR) 12192 from October 18 to 29. Among them, 30 (including 6 X- and 24 M-class) flares originated from the AR core, and the other 5 M-flares appeared at the AR periphery. Four of the X-flares exhibited similar flaring structures, indicating they were homologous flares with an analogous triggering mechanism. The possible scenario is that photospheric motions of emerged magnetic fluxes lead to shearing of the associated coronal magnetic field, which then yields a tether-cutting favorable configuration. Among the five periphery M-flares, four were associated with jet activities. The HMI vertical magnetic field data show that the photospheric fluxes of opposite magnetic polarities emerged, converged, and canceled with each other at the footpoints of the jets before the flares. Only one M-flare from the AR periphery was followed by a coronal mass ejection (CME). From October 20 to 26, the mean decay index of the horizontal background field within the height range of 40–105 Mm is below the typical threshold for torus instability onset. This suggests that a strong confinement from the overlying magnetic field might be responsible for the poor CME production of AR 12192.

• OSTI ID: 22518927
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 808; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
JETS
MAGNETIC FIELDS
MAGNETIC FLUX
MASS
PHOTOSPHERE
SHEAR
SOLAR CORONA
SOLAR FLARES
SUN
ULTRAVIOLET RADIATION