EVOLUTION OF MAGNETIC FIELD AND ENERGY IN A MAJOR ERUPTIVE ACTIVE REGION BASED ON SDO/HMI OBSERVATION

By Xudong Sun, J. Todd Hoeksema, Yang Liu, T. Wiegelmann, K. Hayashi, Qingrong Chen, J. Thalmann. 2011

311 citations recorded by the source corpus.

We report the evolution of the magnetic field and its energy in NOAA active region 11158 over five days based on a vector magnetogram series from the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory (SDO). Fast flux emergence and strong shearing motion led to a quadrupolar sunspot complex that produced several major eruptions, including the first X-class flare of Solar Cycle 24. Extrapolated nonlinear force-free coronal fields show substantial electric current and free energy increase during early flux emergence near a low-lying sigmoidal filament with a sheared kilogauss field in the filament channel. The computed magnetic free energy reaches a maximum of ∼2.6 × 1032 erg, about 50% of which is stored below 6 Mm. It decreases by ∼0.3 × 1032 erg within 1 hr of the X-class flare, which is likely an underestimation of the actual energy loss. During the flare, the photospheric field changed rapidly: the horizontal field was enhanced by 28% in the core region, becoming more inclined and more parallel to the polarity inversion line. Such change is consistent with the conjectured coronal field “implosion” and is supported by the coronal loop retraction observed by the Atmospheric Imaging Assembly (AIA). The extrapolated field becomes more “compact” after the flare, with shorter loops in the core region, probably because of reconnection. The coronal field becomes slightly more sheared in the lowest layer, relaxes faster with height, and is overall less energetic.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/e64072c90087d4504f79cf153b1f26cfaddf6d49

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In Astronomy and Astrophysics

Citations in the corpus

The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs – Space-Weather HMI Active Region Patches (2014, methodology): “The expression relating the final CEA map coordinate [x, y] to the heliographic longitude and latitude [φ, λ] follows Equations (79) and (80) of Calabretta and Greisen (2002), compliant with the World Coordinate System (WCS) standard (e.g. Thompson, 2006).”
THERMAL DIAGNOSTICS WITH THE ATMOSPHERIC IMAGING ASSEMBLY ON BOARD THE SOLAR DYNAMICS OBSERVATORY: A VALIDATED METHOD FOR DIFFERENTIAL EMISSION MEASURE INVERSIONS (2015, background): “2 flare (see, e.g., Schrijver et al. 2011; Sun et al. 2012), two M-class flares and more than a dozen C-class flares.”
PLASMOID EJECTIONS AND LOOP CONTRACTIONS IN AN ERUPTIVE M7.7 SOLAR FLARE: EVIDENCE OF PARTICLE ACCELERATION AND HEATING IN MAGNETIC RECONNECTION OUTFLOWS (2013, background): “For example, pre-existing coronal loops can contract at typical speeds <100 kms−1 during eruptions (Liu & Wang 2010; Liu et al. 2012a; Sun et al. 2012), interpreted as implosion (Hudson 2000; Janse & Low 2007) due to the rapid release of magnetic energy and thus reduction of magnetic pressure…”
WHY IS THE GREAT SOLAR ACTIVE REGION 12192 FLARE-RICH BUT CME-POOR? (2015, methodology): “We note that Ef should be taken as an order of magnitude estimate as the systematic uncertainty can be large (Sun et al. 2012).”
ELECTRIC CURRENTS IN FLARE RIBBONS: OBSERVATIONS AND THREE-DIMENSIONAL STANDARD MODEL (2014, methodology): “Sun et al. (2012), Wang et al. (2012), and Petrie (2013) found that the horizontal photospheric magnetic field was enhanced and more sheared in between the flare ribbons by about 30% after the X2.”
Solar Force-free Magnetic Fields (2012, methodology): “Régnier and Amari (2004), Valori et al. (2012) and Sun et al. (2012) applied the Grad–Rubin, MHD-relaxation and optimization approach, respectively and found at least qualitatively a good agreement of NLFFFmodels with observed sigmoid or serpentine structures.”
THE CENTRAL MOLECULAR GAS STRUCTURE IN LINERS WITH LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI: EVIDENCE FOR GRADUAL DISAPPEARANCE OF THE TORUS (2012, background): “2) of the Solar Cycle 24 and its energetics have been studied thoroughly by Sun et al. (2012).”
The Interaction of Successive Coronal Mass Ejections: A Review (2016, methodology): “A well studied case is AR 11158 based on the SDO/HMI vector magnetograms (see, e.g., Schrijver et al., 2011, Sun et al., 2012, SOLA: Review_v4.tex; 16 March 2017; 5:40; p. 5 Wang et al., 2012, Vemareddy, Ambastha, and Maurya, 2012).”