Proper Motion of Individual Sunspot and Photospheric Magnetic Properties Related to X-class Flare in NOAA AR12158
Dhani Herdiwijaya, Arifa Eva Celinia Candra, Chandra Alif Fernanda, Miftahul Husna

Astronomy Division, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Ganesha 10 Bandung, Indonesia 40132

Abstract

Sunspots and their dynamics dominate the magnetic topology and evolution of both the photosphere and the overlying coronal active regions. Thus, a comprehensive understanding of their behaviour is essential to understanding the solar magnetic field represented by white-light images and magnetogram data. Based on high resolution images obtained from Helioseismic and Magnetic Imager (HMI) instrument onboard Solar Dynamic Observatory (SDO) satellite at visual wavelength, we traced individual umbral sunspots to find drift motion during flare occurrences within NOAA Active Region (AR) 12158 (N11E05) from September 7 to 11, 2014. We measured relative motion of 111 sunspots in 151 frames. The sunspot group was characterized by about 440 millionth solar hemisphere in the area and complex magnetic morphology with beta-gamma-delta class. Photospheric magnetic properties through SHARP parameters, based on SDO/HMI continuum and magnetogram were computed. We found a strong relation of rotation motion and variability of magnetic characteristics before and post-flare. Some sunspots showed faster motion and moved slowly nearly along the magnetic field polarity inversion line that showed shear motion. Large-scale twisting or helicity of sunspot magnetic flux tubes posed implications with the build-up of instabilities that may lead to eruptions. Flare outburst which is occurred in corona layer affected sunspot motion and area, as seen for their changing configuration and morphology, before and after peaked X-ray intensity. This result indicates that there is a strong connection between X-ray solar flare at corona layer and its foot points motion at photosphere.

Keywords: Sun: activity, flares, photosphere, magnetic fields, sunspots

Topic: EARTH, ATMOSPHERIC, AND SPACE SCIENCE