Flares and Magnetic Non-potentiality of NOAA AR 11158

Abstract

The magnetic non-potentiality is important for understanding flares and other solar activities in active regions (ARs). Five non-potential parameters, i.e., electric current, current helicity, source field, photospheric free energy, and angular shear, are calculated in this work to quantify the non-potentiality of NOAA AR 11158. Benefited from high spatial resolution, high cadence, and continuously temporal coverage of vector magnetograms from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, both the long-term evolution of the AR and the rapid change during flares have been studied. We confirmed that, comparing with the magnetic flux, the magnetic non-potentiality has a closer connection with the flare, and the emerging flux regions are important for the magnetic non-potentiality and flares. The main results of this work are as follows. (1) The vortex in the source field directly displays the deflection of horizontal magnetic field. The deflection is corresponding to the fast rotated sunspot with a time delay, which suggests that the sunspot rotation leads to an increase of the non-potentiality. (2) Two areas that have evident changes of the azimuth of the vector magnetic field are found near the magnetic polarity inversion line. The change rates of the azimuth are about 1.3 deg/h and 3.6 deg/h, respectively. (3) Rapid and prominent increases are found in the variation of helicity during four flares in their initial brightening regions. The recovery of the increases takes 3-4 h for the two biggest flares (X2.2 and M6.6), while only takes about 2 h for the other two smaller flares (M2.2 and M1.6).

13 pages, 7 figures, accepted to Research in Astronomy and Astrophysics (RAA)

References in corpus (7)

• Evolution of Magnetic Field and Energy in A Major Eruptive Active Region Based on SDO/HMI Observation
• Non-linear force-free field modeling of a solar active region around the time of a major flare and coronal mass ejection
• Interaction between a fast rotating sunspot and ephemeral regions as the origin of the major solar event on 2006 December 13
• Evidence for collapsing fields in corona and photosphere during the 15 February 2011 X2.2 flare: SDO AIA and HMI Observations
• Time delays in quasi-periodic pulsations observed during the X2.2 solar flare on 2011 February 15
• Magneto--Acoustic Energetics Study of the Seismically Active Flare of 15 February 2011
• Horizontal flows concurrent with an X2.2 flare in active region NOAA 11158

Cited by in corpus (10)

• Block-induced complex structures building the flare-productive solar active region 12673
• Interpreting Eruptive Behavior in NOAA AR 11158 via the Region's Magnetic Energy and Relative Helicity Budgets
• Structure and Evolution of Magnetic Fields Associated with Solar Eruptions (Invited Review)
• On the relationship between sunspot structure and magnetic field changes associated with solar flares
• 3-D nonlinear force-free field reconstruction of solar active region 11158 by direct boundary integral equation
• Dark Post-Flare Loops Observed by Solar Dynamics Observatory
• Time Series Analysis of Photospheric Magnetic Parameters of Flare-quiet versus Flaring Active Regions: Scaling Properties of Fluctuations
• On the line profile changes observed during the X2.2 class flare in the active region NOAA 11158
• Photospheric Magnetic Free Energy Density of Solar Active Regions
• Solar Sources of Interplanetary Magnetic Clouds Leading to Helicity Prediction