The Solar Mean Magnetic Field (SMMF) is generally defined as the disc-averaged line-of-sight (LOS) magnetic field on the sun. The role of the active regions and the large-scale magnetic field structures (also called the background) has been debated over the past few decades to understand whether the origin of the SMMF is either due to the active regions or the background. We, in this paper have investigated contribution of sunspots, plages, networks and the background towards the variability of the SMMF using the datasets from the SDO-AIA & HMI, and found that 89% of the SMMF is due to the background whereas the remaining 11% originates from the active regions and the networks.

Initiation and development of a M 1.0 class flare of June 12, 2014, was observed by space and ground-based telescopes, including EUV and X-ray imaging spectroscopy by IRIS and RHESSI, and high-resolution optical imaging by 1.6 m New Solar Telescope (NST). Analyzing the NST data, we found small-scale loop-like structures in the region of the magnetic field Polarity Inversion Line (PIL), the emergence and interaction of which caused photospheric brightenings temporarily coinciding with hard X-ray impulses. Detailed studies of the PIL region reveal signatures of photospheric plasma downflows and dissipation of electric currents. The reconstructed magnetic field topology shows a bundle of lines connecting the PIL region with the flare ribbons which were places of chromospheric evaporation observed by IRIS. The observations suggest a scenario with the primary energy release processes located in the low atmospheric layers of the PIL, energizing the overlying large-scale magnetic structure and causing “gentle” chromospheric evaporation.

Understanding the mechanism that causes the emergence of magnetic flux from the solar interior to the atmosphere, the drastic changes in the properties of the matter and magnetic fields along the rise and the interplay of dynamic and resistive phenomena that shape the emerged regions is one of the major open tasks in solar physics. Important advances are being made both in the theoretical modelling and in the observation of the emergence events. This review concentrates on recent advances through 3D numerical experiments carried out with massively parallel MHD and radiative transfer codes.