Variations of the Photospheric Magnetic Field Following the Eruptive Event on June 7, 2011

Field variations in the region of the eruptive event on June 7, 2011 are studied based on vector measurements of the photospheric magnetic field by the SDO/HMI instrument. Variations of the modulus (B), the radial (B_r) and the transverse (B_t) components of the magnetic induction, and the inclination angle (α) of the field lines to the radial direction from the center of the Sun are analyzed. It is found that, in the part of the flare region near the polarity inversion line (PIL) after the onset of the flare, the magnitude and the transverse component of the magnetic induction as well as the angles α abruptly increase. During the slow rise of filament near its channel, the inclination angles of the field lines decrease. It is shown that diverging flare ribbons are above the regions of the photosphere with local maxima of the field modulus and with deep minima of the inclination angles of the field lines at all stages of their existence over their entire length with the exception of small areas. It is established that the azimuth decreases after the onset of the flare near the PIL of the photospheric magnetic field, which means an increase in the shear. On the contrary, at a distance from the PIL there is a slight decrease in the shear.