Related papers: Why Is the Great Solar Active Region 12192 Flare-R…
A magnetic power spectral analysis is performed on 53 solar active regions, observed from August 2011 to July 2012. Magnetic field data obtained from the Helioseismic and Magnetic Imager, inverted as Active Region Patches, are used to study…
Extreme solar particle events reveal that the Sun can occasionally produce eruptions significantly more energetic than those observed in the modern era. These events are thought to originate from powerful coronal mass ejections, typically…
At the Sun, the strongest magnetic fields are routinely detected at dark sunspots. The magnitude of the field is typically about 3000 G, with only a few exceptions that reported the magnetic field in excess of 5000 G. Given that the…
On 2010 August 14, a wide-angled coronal mass ejection (CME) was observed. This solar eruption originated from a destabilized filament that connected two active regions and the unwinding of this filament gave the eruption an untwisting…
This is the first of four companion papers, which analyze a complex eruptive event of 18 November 2003 in AR 10501 and the causes of the largest Solar Cycle 23 geomagnetic storm on 20 November 2003. Analysis of a complete data set, not…
We carried out a multi-wavelength study of a CME and a medium-size 1B/C1.3 flare occurring on 12 May 1997. We present the investigation of magnetic-field variations in the NOAA Active Region 8038 which was observed on the Sun during 7--16…
The properties of active region nests, which are locations on the Sun with recurring flux emergence, are poorly constrained by observations from Earth alone. ESA's Solar Orbiter now monitors the far side of the Sun for extended periods of…
We study the role of rotating sunspots in relation to the evolution of various physical parameters characterizing the non-potentiality of the active region NOAA 11158 and its eruptive events using the magnetic field data from the…
We investigated how the magnetic field in solar active regions (ARs) controls flare activity, i.e., whether a confined or eruptive flare occurs. We analyzed 44 flares of GOES class M5.0 and larger that occurred during 2011--2015. We used 3D…
We investigate the occurrence of a CME-driven coronal dimming using unique high resolution spectral images of the corona from the Hinode spacecraft. Over the course of the dimming event we observe the dynamic increase of non-thermal line…
We compare the coronal magnetic energy and helicity of two solar active regions (ARs), prolific in major eruptive (AR~11158) and confined (AR~12192) flaring, and analyze the potential of deduced proxies to forecast upcoming flares. Based on…
On 2005 January 15, the active region AR10720 produced an X1.2 solar flare that induced high levels of seismicity into the photospheric layers. The seismic source was detected using helioseismic holography and analysed in detail in Paper I.…
The dynamics of active region (AR) 12673 is qualitatively studied using observational data obtained with the Helioseismic and Magnetic Imager of the Solar Dynamics Observatory on August 31--September 8, 2017. This AR was remarkable for its…
Coronal mass ejections (CMEs) are large-scale eruptions of plasma from the coronae of stars. Understanding the plasma processes involved in CME initiation has applications to space weather forecasting and laboratory plasma experiments.…
The question of the nature of precursors of solar flares, as well as their relationship with subsequent flares, still has no unambiguous answer. This is due, in particular, to the lack of systematic statistical work, the relative…
How eruption can recur from a confined magnetic structure is discussed based on the {\it Solar Dynamics Observatory} (SDO) observations of the NOAA active region 11444, which produced three eruptions within 1.5 hours on March 27, 2012. The…
In this paper, we focus on the pre-flare coronal dimmings. We report our multiwavelength observations of the GOES X1.6 solar flare and the accompanying halo CME produced by the eruption of a sigmoidal magnetic flux rope (MFR) in NOAA active…
The flux of energetic particles originating from the Sun fluctuates during the solar cycles. It depends on the number and properties of Active Regions (ARs) present in a single day and associated solar activities, such as solar flares and…
In our earlier study of this series (Park et al. 2020, Paper I), we examined the hemispheric sign preference (HSP) of magnetic helicity flux $dH/dt$ across photospheric surfaces of 4802 samples of 1105 unique active regions (ARs) observed…
The Sun is the major source of heat and light in our solar system. The solar cycle is the 11-year cycle of solar activity that can be determined by the rise and fall in the numbers and surface area of sunspots. Solar activity is associated…