Solar eruptive phenomena, like flares and coronal mass ejections (CMEs), are explosive events occurring in the solar atmosphere that involve the rapid release of huge quantities of energy. The electromagnetic radiation, energetic particles and magnetic field produced by flares and carried by CMEs can affect interplanetary space weather and Earth's geomagnetic field, leading to effects like disruption of satellite navigation systems and failure of power grids at high latitudes. This makes an understanding of the eruptive phenomena quite indispensable.
In this talk I will present a magnetohydrodynamics simulation study of active region NOAA 11283 initialised using a non-force-free magnetic field extrapolated from a photospheric vector magnetogram. In particular, I would focus on the magnetic reconnections at a magnetic null point that resulted in the X2.1 flare on 2011 September 6 around 22:21 UT followed by the appearance of circular flare ribbons and coronal dimmings (transient regions of reduced coronal emission in extreme-ultraviolet).
