Related papers: Extreme solar events
Solar energetic protons (SEPs) in different energy channels from 10 to above 100 MeV are analyzed and their relationship to solar and geomagnetic activity is investigated. We performed temporal association analysis between the SEPs, solar…
Solar flares are often accompanied by filament/prominence eruptions ($\sim10^{4}$ K and $\sim 10^{10-11}$ cm$^{-3}$), sometimes leading to coronal mass ejections (CMEs) that directly affect the Earth's environment. `Superflares' are found…
Whether the Sun is an ordinary G-type star is still an open scientific question. Stellar surveys by Kepler and TESS, however, revealed that Sun-like stars tend to show much stronger flare activity than the Sun. This study aims to reassess…
Several recurrent X-class flares from Active Region (AR) 13664 have triggered a severe G5-class geomagnetic storm between May 10 and 11, 2024. The morphology and compactness of this AR closely resemble the active region responsible for the…
Although the Sun is our closest star by many orders of magnitude and despite having sunspot records stretching back to ancient China, our knowledge of the Sun's magnetic field is far from complete. Indeed, even now, after decades of study,…
The physical processes, which drive powerful solar eruptions, play an important role in our understanding of the Sun-Earth connection. In this Special Issue, we firstly discuss how magnetic fields emerge from the solar interior to the solar…
Since the first observations of solar oscillations in 1962, helioseismology has probably been one of the most successful fields of astrophysics. Besides the improvement of observational data, solar seismologists developed sophisticated…
In September 1859 the Colaba observatory measured the most extreme geomagnetic disturbance ever recorded at low latitudes related to solar activity: the Carrington storm. This paper describes a geomagnetic disturbance case with a profile…
Solar flares and coronal mass ejections are among the most prominent manifestations of the magnetic activity of the Sun. The strongest events of them tend to occur in active regions (ARs) that are large, complex, and dynamically evolving.…
In addition to several recent articles devoted to the rare event of ground-level enhancement of the solar relativistic proton flux observed on 2021 October 28 (GLE73), we study the 10-100 MeV solar energetic particle (SEP) component of this…
There has been tremendous progress in observing oscillations in solar-type stars. In a few short years we have moved from ambiguous detections to firm measurements. We briefly review the recent results, most of which have come from…
Extreme Scattering Events (ESEs) are attributed to radio-wave refraction by a cloud of free-electrons crossing the line-of-sight. We present a new model in which these electrons form the photo-ionized 'skin' of an underlying cool,…
There has been global attention focused on extreme climatic changes. The purpose of this paper is to explore the response of extreme precipitation events to solar activity, over Kerala, India. The three solar indices - sunspot number, F10.7…
Solar flares (SFs) are sudden brightening observed over the Sun surface which is associated with a large energy release. Flares with burst of Xray emission are normally followed by a mass ejection of electrons and ions from the solar…
Context. A solar eruption on 17 April 2021 produced a widespread Solar Energetic Particle (SEP) event that was observed by five longitudinally well-separated observers in the inner heliosphere at heliocentric distances of 0.42 to 1 au:…
The SOL2014-09-01 far-side solar eruptive event produced hard electromagnetic and radio emissions observed with detectors at near-Earth vantage points. Especially challenging was a long-duration >100 MeV $\gamma$-ray burst probably produced…
Since their discovery more than 60 years ago, accreting supermassive black holes in active galactic nuclei (AGN) were recognized as highly variable sources, requiring an extremely compact, dynamic environment. Their variability traces to…
In this last Paper III additional evidences that the solar high energetic particles radiation with energies higher as 100 MeV (the solar cosmic rays SCR) is an very important component for the "Sun- climate" relationship are given (see also…
We present a study of three highly non-radial solar wind events when the azimuthal solar wind flow angle exceeds > 6 degrees for one day or more. None of the events are associated with coronal mass ejections and co-rotating interaction…
The elemental composition of the Sun's hot atmosphere, the corona, shows a distinctive pattern that is different than the underlying surface, or photosphere (Pottasch 1963). Elements that are easy to ionize in the chromosphere are enhanced…