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Solar flares are sudden energy release events in the solar corona, resulting from magnetic reconnection, that accelerates particles and heats the ambient plasma. During a flare, there are often multiple, temporally and spatially separated…

Solar and Stellar Astrophysics · Physics 2020-12-02 Rohit Sharma , Marina Battaglia , Yingjie Luo , Bin Chen , Sijie Yu

The solar X-ray irradiance is significantly heightened during the course of a solar flare, which can cause radio blackouts due to ionization of the atoms in the ionosphere. As the duration of a solar flare is not related to the size of that…

Solar and Stellar Astrophysics · Physics 2021-11-10 Jeffrey W. Reep , Will T. Barnes

Analysis of spectra obtained with the gamma-ray spectrometer SPI onboard INTEGRAL of the GOES X17-class flare on October 28, 2003 is presented. In the energy range 600 keV - 8 MeV three prominent narrow lines at 2.223, 4.4 and 6.1 MeV,…

Astrophysics · Physics 2009-11-11 J. Kiener , M. Gros , V. Tatischeff , G. Weidenspointner

We analyze H-alpha images, soft X-ray profiles, magnetograms, extreme ultra-violet images and radio observations of two homologous flare events (M1.4/1N and M9.6/2B) on 20 November 2003 in the active region NOAA 10501 and study properties…

Solar and Stellar Astrophysics · Physics 2015-05-14 Pankaj Kumar , P. K. Manoharan , Wahab Uddin

We report on a large stellar flare from the nearby dMe flare star EV Lac observed by the Swift and Konus-Wind satellites and the Liverpool Telescope. It is the first large stellar flare from a dMe flare star to result in a Swift trigger…

Generally, large solar flares accelerate electrons to high energies more efficiently than microflares. However, some microflares, known as hard microflares (HMFs), also produce high-energy electrons, as indicated by their flat hard X-ray…

Impulsive solar energetic electrons are often observed in the interplanetary space near the Earth and have an attractive diagnostic potential for poorly understood solar flare acceleration processes. We investigate the transport of solar…

Solar and Stellar Astrophysics · Physics 2009-11-13 E. P. Kontar , H. A. S. Reid

This paper presents data from first GPS measurements of global response of the ionosphere to solar flares of September 23, 1998 and July 29, 1999. The analysis used novel technology of a global detection of ionospheric effects from solar…

The X2.2-class solar flare of February 15, 2011, produced a powerful `sunquake' event, representing a seismic response to the flare impact. The impulsively excited seismic waves formed a compact wavepacket traveling through the solar…

Solar and Stellar Astrophysics · Physics 2011-02-22 A. G. Kosovichev

Solar eclipse is an unique opportunity to study the lower ionospheric variabilities under a controlled perturbation when the solar ultraviolet and X-ray are temporally occulted by the lunar disk. Sub-ionospheric Very Low Frequency (VLF)…

Earth and Planetary Astrophysics · Physics 2018-07-04 Sandip K. Chakrabarti , Sudipta Sasmal , Tamal Basak , Suman Chakraborty , Robert L. Tucker

Decimetric radio observations of the impulsive solar flare on October 5, 1992, 09:25 UT show a long series of quasi-periodic pulsations deeply modulating a continuum in the 0.6-2 GHz range that is slowly drifting toward lower frequencies.…

Astrophysics · Physics 2007-05-23 B. Kliem , M. Karlicky , A. O. Benz

The timing of 503 solar flares observed simultaneously in hard X-rays, soft X-rays and H-alpha is analyzed. We investigated the start and the peak time differences in different wavelengths, as well as the differences between the end of the…

Astrophysics · Physics 2015-06-24 A. Veronig , B. Vrsnak , M. Temmer , A. Hanslmeier

Solar flares result in an increase of the solar irradiance at all wavelengths. While the distribution of the flare fluence observed in coronal emission has been widely studied and found to scale as f(E) ~ E^{-\alpha}, with \alpha slightly…

Solar and Stellar Astrophysics · Physics 2015-10-08 M. Kretzschmar

We investigated in detail the M5.8 class solar flare that occurred on 2023-03-06. This flare was one of the first strong flares observed by the Siberian Radioheliograph in the microwave range and the Advanced Space-based Solar Observatory…

Solar and Stellar Astrophysics · Physics 2024-05-30 Alexey Kuznetsov , Zhao Wu , Sergey Anfinogentov , Yang Su , Yao Chen

High-energy solar flares have shown to have at least two distinct phases: prompt-impulsive and delayed-gradual. Identifying the mechanism responsible for accelerating the electrons and ions and the site at which it occurs during these two…

Solar and Stellar Astrophysics · Physics 2021-09-29 Melissa Pesce-Rollins , Nicola Omodei , Vahe' Petrosian , Francesco Longo

Three phases are typically observed during solar flares: the preflare, impulsive, and decay phases. During the impulsive phase, it is believed that the electrons and other particles are accelerated after the stored energy in the magnetic…

Solar and Stellar Astrophysics · Physics 2016-02-15 W. G. Fajardo-Mendieta , J. C. Martínez-Oliveros , J. D. Alvarado-Gómez , B. Calvo-Mozo

The X9.3 flare of September 6, 2017, was the most powerful flare of Solar Cycle 24. It generated strong white-light emission and multiple helioseismic waves (sunquakes). By using data from Helioseismic and Magnetic Imager (HMI) onboard the…

Solar and Stellar Astrophysics · Physics 2018-09-19 Ivan N. Sharykin , Alexander G. Kosovichev

Solar eruptions, known as Coronal Mass Ejections (CMEs), are frequently observed on our Sun. Recent Kepler observations of superflares on G-type stars have implied that so called super-CMEs, possessing kinetic energies 10 times of the most…

Solar and Stellar Astrophysics · Physics 2014-10-29 Vladimir S. Airapetian , Alex Glocer , William Danchi

The impact of solar-stellar activity on planetary environments is a topic of great interest within the Sun-Earth system as well as exoplanetary systems. In particular, extreme events such as flares and coronal mass ejections have a profound…

Solar and Stellar Astrophysics · Physics 2025-01-17 Priyansh Jaswal , Suvadip Sinha , Dibyendu Nandy

In the present work we study Hinode/EIS observations of an active region taken before, during and after a small C2.0 flare in order to monitor the evolution of the magnetic field evolution and its relation to the flare event. We find that…

Solar and Stellar Astrophysics · Physics 2021-05-26 Enrico Landi , Wenxian Li , Tomas Brage , Roger Hutton