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Slow magnetoacoustic waves in a static background provide a seismological tool to probe the solar atmosphere in the analytic frame. By analyzing the spatiotemporal variation of the electron number density of plume structure in coronal holes…

Solar and Stellar Astrophysics · Physics 2020-09-09 Il-Hyun Cho , Valery M. Nakariakov , Yong-Jae Moon , Jin-Yi Lee , Dae Jung Yu , Kyung-Suk Cho , Vasyl Yurchyshyn , Harim Lee

Coronal waves, significant solar phenomena, act as diagnostic tools for scientists studying solar atmosphere properties. Here, we present a novel observation detailing how a coronal wave event, associated with an X5.0 class flare,…

To understand the mechanism of coronal heating, it is crucial to derive the contribution of small-scale flares, the so-called nanoflares, to the heating up of the solar corona. To date, several studies have tried to derive the occurrence…

Solar and Stellar Astrophysics · Physics 2021-01-06 Toshiki Kawai , Shinsuke Imada

Two coherent radio emission mechanisms operate in stellar coronae: plasma emission and cyclotron emission. They directly probe the electron density and magnetic field strength respectively. Most stellar radio detections have been made at…

Solar and Stellar Astrophysics · Physics 2020-11-11 H. K. Vedantham

Stealth coronal mass ejections (CMEs) are eruptions from the Sun that have no obvious low coronal signature. These CMEs are characteristically slower events, but can still be geoeffective and affect space weather at Earth. Therefore,…

Solar and Stellar Astrophysics · Physics 2019-09-11 Jennifer O'kane , Lucie Green , David M. Long , Hamish Reid

Determining the nature of emission processes at the heart of quasars is critical for understanding environments of supermassive black holes. One of the key open questions is the origin of long-wavelength emission from radio-quiet quasars.…

Astrophysics of Galaxies · Physics 2025-09-17 M. Rybak , D. Sluse , K. K. Gupta , M. Millon , E. Behar , F. Courbin , J. P. McKean , H. R. Stacey

Context. There remains much mystery about how or if wave-energy in the photosphere can be transferred sufficiently upwards through the solar atmosphere to contribute to coronal heating. In light of a plethora of theoretical and idealised…

Solar and Stellar Astrophysics · Physics 2026-01-14 George Cherry , Boris Gudiksen , Adam J. Finley , Quentin Noraz

Quiet sun meterwave emission arises from thermal bremsstrahlung in the MK corona, and can potentially be a rich source of coronal diagnostics. On its way to the observer, it gets modified substantially due to the propagation effects -…

Solar and Stellar Astrophysics · Physics 2020-12-29 Rohit Sharma , Divya Oberoi

High resolution spectra from the Hinode EUV Imaging Spectrometer (EIS) have revealed that coronal spectral line profiles are sometimes asymmetric, with a faint enhancement in the blue wing on the order of 100 km/s. These asymmetries could…

Solar and Stellar Astrophysics · Physics 2015-06-11 David H. Brooks , Harry P. Warren

One of the most commonly observed solar radio sources in the metric and decametric wavelengths is the solar noise storm. These are generally associated with active regions and are believed to be powered by the plasma emission mechanism.…

Solar and Stellar Astrophysics · Physics 2025-08-19 Surajit Mondal , Peijin Zhang , Devojyoti Kansabanik , Divya Oberoi , Gillian Pearce

The physics of solar flares occurring on the Sun is highly complex and far from fully understood. However, observations show that solar eruptions are associated with the intense kilogauss fields of active regions, where free energies are…

Solar and Stellar Astrophysics · Physics 2024-01-26 Bach Viet Do , Yang Chen , XuanLong Nguyen , Ward Manchester

Solar flares result from the rapid conversion of stored magnetic energy within the Sun's corona. These energy releases are associated with coronal magnetic loops, which are rooted in dense photospheric plasma and are passively transported…

Solar and Stellar Astrophysics · Physics 2025-03-28 M. Berretti , S. Mestici , L. Giovannelli , D. Del Moro , M. Stangalini , F. Giannattasio , F. Berrilli

This work focuses on the combination of White Light (WL) and UV (Ly-alpha) coronagraphic images to demonstrate the capability to measure the solar wind speed in the inner corona directly with the ratio between these two images (a technique…

Solar and Stellar Astrophysics · Physics 2021-10-13 Alessandro Bemporad , Silvio Giordano , Luca Zangrilli , Federica Frassati

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…

Solar and Stellar Astrophysics · Physics 2022-05-18 David H. Brooks , Deborah Baker , Lidia van Driel-Gesztelyi , Harry P. Warren , Stephanie L. Yardley

Solar flare forecasting mainly relies on photospheric magnetograms and associated physical features to predict forthcoming flares. However, it is believed that flare initiation mechanisms often originate in the chromosphere and the lower…

Solar and Stellar Astrophysics · Physics 2024-10-22 Grégoire Francisco , Sabrina Guastavino , Teresa Barata , João Fernandes , Dario Del Moro

Outflows perpendicular to the guide field are believed to be a possible signature of magnetic reconnection in the solar corona and specifically a way to detect the occurrence of ubiquitous small-angle magnetic reconnection. The aim of this…

Solar and Stellar Astrophysics · Physics 2025-03-05 G. Cozzo , P. Pagano , F. Reale , P. Testa , A. Petralia , J. Martinez-Sykora , V. Hansteen , B. De Pontieu

Several mechanisms have been proposed to explain the transient seis- mic emission, i.e., sunquakes, from some solar flares. Some theories associate high-energy electrons and/or white-light emission with sunquakes. High-energy charged…

Solar and Stellar Astrophysics · Physics 2015-12-09 J. C. Buitrago-Casas , J. C. Martinez Oliveros , C. Lindsey , B. Calvo-Mozo , S. Krucker , L. Glesener , S. Zharkov

During a solar flare, it is believed that reconnection takes place in the corona followed by fast energy transport to the chromosphere. The resulting intense heating strongly disturbs the chromospheric structure, and induces complex…

Solar and Stellar Astrophysics · Physics 2019-04-30 Christopher M. J. Osborne , John A. Armstrong , Lyndsay Fletcher

In this article, an active contours without edges (ACWE)-based algorithm has been proposed for the detection of solar filaments in H-alpha full-disk solar images. The overall algorithm consists of three main steps of image processing. These…

Computer Vision and Pattern Recognition · Computer Science 2024-12-31 Sanmoy Bandyopadhyay , Vaibhav Pant

Solar eruptions are usually associated with a variety of phenomena occurring in the low corona before, during, and after onset of eruption. Though easily visible in coronagraph observations, so-called stealth coronal mass ejections (CMEs)…

Solar and Stellar Astrophysics · Physics 2015-06-22 E. D'Huys , D. B. Seaton , S. Poedts , D. Berghmans