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We investigate how the splitting of the leading sunspot and associated flux emergence and cancellation in active region NOAA 11515 caused an eruptive M5.6 flare on 2012 July 2. Our study employs multi-wavelength observations from HMI, AIA…

During late October 2014, active region NOAA 2192 caused an unusual high level of solar activity, within an otherwise weak solar cycle. While crossing the solar disk, during a period of 11 days, it was the source of 114 flares of GOES class…

In the first half of May 2024, the solar active region (AR)13664 was responsible for generating the strongest geomagnetic storm in over 20 years, through an enhanced production of X-class flares and coronal mass ejections (CMEs). A key…

We report on an eruption involving a relatively rare filament-filament interaction on 2013 June 21, observed by SDO and STEREO-B. The two filaments were separated in height with a 'double-decker' configuration. The eruption of the lower…

Solar flares occur due to the sudden release of energy stored in active-region magnetic fields. To date, the pre-cursors to flaring are still not fully understood, although there is evidence that flaring is related to changes in the…

The unusually large NOAA active region 2192, observed in October 2014, was outstanding in its productivity of major two-ribbon flares without coronal mass ejections. On a large scale, a predominantly north-south oriented magnetic system of…

The largest magnetic storm in solar cycle 24 was caused by a fast coronal mass ejection (CME) that was related to a small C9.1 flare that occurred on 15 March 2015 in solar active region (AR) NOAA 12297. The purpose of this study is to…

The partial eruption of a filament channel with bifurcated substructures is investigated using datasets obtained from both ground-based and space-borne facilities. Small-scale flux reconnection/cancellation events in the region triggered…

Sunspot proper motions and flares of a super active region NOAA 5395, which was the biggest and the most flare-active region in the 22nd sunspot cycle, were analyzed in details. We measured sunspot proper motions by using the H-alpha - 5.0…

Vector magnetograms taken at Huairou Solar Observing Station (HSOS) and Mees Solar Observatory (MSO) reveal that the super active region (AR) NOAA 10486 was a complex region containing current helicity flux of opposite signs. The main…

We analyze the temporal evolution of the three-dimensional (3D) magnetic structure of the flaring active region (AR) NOAA 10930 by using the nonlinear force-free fields extrapolated from the photospheric vector magnetic fields observed by…

Solar active regions and the processes that occur in them have been extensively studied and analyzed and many types of models and characterizations have been proposed for the occurrence of different eruptive events that take place in the…

We report a study of a compound solar eruption that was associated with two consecutively erupting magnetic structures and correspondingly two distinct peaks, during impulsive phase, of an M-class flare (M8.5). Simultaneous multi-viewpoint…

Using the photospheric magnetic and coronal observations of Solar Dynamics Observatory, we studied the build-up and eruption of coronal non-potential magnetic structure in emerging active region (AR) 12673. The velocity field derived from…

A solar active region (AR) that produces at least one M- or X-class major flare tends to produce multiple flares during its passage across the solar disk. It will be interesting if we can estimate how flare-productive a given major flaring…

$\delta$-sunspots, with highly complex magnetic structures, are very productive in energetic eruptive events, such as X-class flares and homologous eruptions. We here study the formation of such complex magnetic structures by numerical…

Large, complex, active regions may produce multiple flares within a certain period of one or two days. These flares could occur in the same location with similar morphologies, commonly referred to as homologous flares. In 2011 September,…

Filament eruptions often result in flares and coronal mass ejections (CMEs). Most studies attribute the filament eruptions to their instabilities or magnetic reconnection. In this study, we report a unique observation of a filament eruption…

The non-association of coronal mass ejections with high energetic flares is sparse. For this reason, the magnetic conditions required for the confinedness of major flares is a topic of active research. Using multi-instrument observations,…

Active region NOAA 13842 produced two successive solar flares: an X7.1-class flare on October 1, 2024, and an X9.0-class flare on October 3, 2024. This study continues our previous simulation work that successfully reproduced the X7.1-class…