Horizontal flows concurrent with an X2.2 flare in active region NOAA 11158

Abstract

Horizontal proper motions were measured with local correlation tracking (LCT) techniques in active region NOAA 11158 on 2011 February 15 at a time when a major (X2.2) solar flare occurred. The measurements are based on continuum images and magnetograms of the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. The observed shear flows along the polarity inversion line were rather weak (a few 100 m/s). The counter-streaming region shifted toward the north after the flare. A small circular area with flow speeds of up to 1.2 km/s appeared after the flare near a region of rapid penumbral decay. The LCT signal in this region was provided by small-scale photospheric brigthenings, which were associated with fast traveling moving magnetic features. Umbral strengthening and rapid penumbral decay was observed after the flare. Both phenomena were closely tied to kernels of white-light flare emission. The white-light flare only lasted for about 15 min and peaked 4 min earlier than the X-ray flux. In comparison to other major flares, the X2.2 flare in active region NOAA 11158 only produced diminutive photospheric signatures.

6 pages, 4 figures, accepted for publication in Astronomische Nachrichten/AN

References in corpus (3)

• Response of the Photospheric Magnetic Field to the X2.2 Flare on 2011 February 15
• Sigmoid-to-Flux-Rope Transition Leading to A Loop-Like Coronal Mass Ejection
• Two-Dimensional Spectroscopy of Photospheric Shear Flows in a Small delta Spot

Cited by in corpus (13)

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• Evaluating local correlation tracking using CO5BOLD simulations of solar granulation
• Contracting and Erupting Components of Sigmoidal Active Regions
• Flare-associated type III radio bursts and dynamics of the EUV jet from SDO/AIA and RHESSI observations
• Flares and Magnetic Non-potentiality of NOAA AR 11158
• High-resolution imaging and near-infrared spectroscopy of penumbral decay
• A Helioseismic Survey of Near-surface Flows Around Active Regions and their Association with Flares
• Temporal Evolution of Sunspot Areas and Estimation of Related Plasma Flows
• High-resolution spectroscopy of a surge in an emerging flux region
• Background-subtracted Solar Activity Maps
• Divergent Horizontal Sub-surface Flows within Active Region 11158
• Spatio-temporal scaling of turbulent photospheric line-of-sight magnetic field in active region NOAA 11158