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Related papers: Flare-Driven Plasma Dynamics and Elemental Abundan…

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An integrated Magneto-Fluid model, that accords full treatment to the Velocity fields associated with the directed plasma motion, is developed to investigate the dynamics of coronal structures. It is suggested that the interaction of the…

Thirty years ago Breneman and Stone observed that the enhancement or suppression of element abundances in large solar energetic-particle (SEP) events varies as a power of the mass-to-charge ratio, A/Q, of the elements. Since Q during…

Solar and Stellar Astrophysics · Physics 2016-12-06 Donald V. Reames

This review focuses on the processes that energize and trigger major solar flares and flux-rope destabilizations. Numerical modeling of specific solar regions is hampered by uncertain coronal-field reconstructions and by poorly understood…

Astrophysics · Physics 2009-11-13 C. J. Schrijver

Solar flares are transient yet dramatic events in the atmosphere of the Sun, during which a vast amount of magnetic energy is liberated. This energy is subsequently transported through the solar atmosphere or into the heliosphere, and…

Solar and Stellar Astrophysics · Physics 2022-12-14 Graham S. Kerr

The extreme ultraviolet (EUV) and X-ray radiation emitted during solar flares has been shown to significantly increase the electron density of the Earth's ionosphere. During flares, quasi-periodic pulsations (QPPs) in X-ray flux originating…

Solar and Stellar Astrophysics · Physics 2025-04-11 Aisling N. O'Hare , Susanna Bekker , Laura A. Hayes , Ryan O. Milligan

We investigate the thermal, kinematic and magnetic structure of small-scale heating events in an emerging flux region (EFR). We use high-resolution multi-line observations (including Ca II 8542~\AA, Ca II K, and Fe I 6301~\AA line pair) of…

Solar and Stellar Astrophysics · Physics 2023-09-14 Rahul Yadav , Maria D. Kazachenko , Andrey N. Afanasyev , Jaime de la Cruz Rodríguez , Jorrit Leenaarts

Solar variability investigations that include magnetic energy coupling are paramount to solving many key solar/stellar physics problems, particularly for understanding the temporal variability of magnetic energy redistribution and heating…

Solar and Stellar Astrophysics · Physics 2016-12-28 N. Brice Orange , David L. Chesny , Bruce Gendre , David C. Morris , Hakeem M. Oluseyi

Flux emergence is responsible for various solar eruptions. Combining observation and simulations, we investigate the influence of flux emergence at one footpoint of an arcade on coronal rain as well as induced eruptions. The emergence…

Solar and Stellar Astrophysics · Physics 2023-04-26 Xiaohong Li , Rony Keppens , Yuhao Zhou

We present a unified computational framework which can be used to describe impulsive flares on the Sun and on dMe stars. The models assume that the flare impulsive phase is caused by a beam of charged particles that is accelerated in the…

Solar and Stellar Astrophysics · Physics 2015-08-19 Joel C. Allred , Adam F. Kowalski , Mats Carlsson

From vector measurements of the photospheric magnetic field with the SDO/HMI instrument, we studied the field variations within the 2011 June 7 eruptive event related to the filament eruption (FE), flare, and coronal mass ejection (CME). We…

Solar and Stellar Astrophysics · Physics 2016-11-30 V. G. Fainshtein , Ya. I. Egorov , G. V. Rudenko

Context: The mechanism behind the heating of the solar chromosphere remains unclear. Friction between neutrals and charges is expected to contribute to plasma heating in a partially ionised plasma (PIP). Aims: We aim to study the efficiency…

Solar and Stellar Astrophysics · Physics 2025-09-17 M. M. Gómez Míguez , D. Martínez-Gómez , E. Khomenko , B. Popescu Braileanu , M. Collados , P. S. Cally

The origin of the near-ultraviolet and optical continuum radiation in flares is critical for understanding particle acceleration and impulsive heating in stellar atmospheres. Radiative-hydrodynamic simulations in 1D have shown that high…

Solar and Stellar Astrophysics · Physics 2018-01-10 Adam F. Kowalski , Joel C. Allred

Plasma turbulence cascading from MHD to kinetic scales in the heliospheric plasma is believed to play a key role in coronal heating and fast solar wind acceleration, but the properties of the turbulence remain poorly constrained by…

Solar and Stellar Astrophysics · Physics 2026-02-03 Eduard P. Kontar , A. Gordon Emslie , Daniel L. Clarkson , Alexander Pitna

3He-rich solar energetic particles (SEPs) are believed to be accelerated in solar flares or jets by a mechanism that depends on the ion charge-to-mass (Q/M) ratio. It implies that the flare plasma characteristics (e.g., temperature) may be…

Solar and Stellar Astrophysics · Physics 2021-03-10 R. Bucik , S. M. Mulay , G. M. Mason , N. V. Nitta , M. I. Desai , M. A. Dayeh

The inverse First Ionization Potential (FIP) effect is rarely observed in the solar atmosphere, and this anomaly poses a challenging problem in understanding physical processes driving this chemical fractionation. In this work, we…

Solar and Stellar Astrophysics · Physics 2026-04-14 Juan Martínez-Sykora , Paola Testa , Deborah Baker , Bart De Pontieu

Based on a sample of 1114 flares observed simultaneously in hard X-rays (HXR) by the BATSE instrument and in soft X-rays (SXR) by GOES, we studied several aspects of the Neupert effect and its interpretation in the frame of the…

Astrophysics · Physics 2009-11-07 A. Veronig , B. Vrsnak , B. R. Dennis , M. Temmer , A. Hanslmeier , J. Magdalenic

The million degree plasma of the solar corona must be supplied by the underlying layers of the atmosphere. The mechanism and location of energy release, and the precise source of coronal plasma, remain unresolved. In earlier work we pursued…

Solar and Stellar Astrophysics · Physics 2016-03-23 Stephen J. Bradshaw , James A. Klimchuk

We present new results on the ionization by electron impacts in a dense plasma. We are interested in the density effect known as the ionization potential depression and in its role in atomic structure. Rather than using the well-known…

Atomic Physics · Physics 2023-09-14 Djamel Benredjem , Jean-Christophe Pain , Annette Calisti , Sandrine Ferri

We have explored the relationship between hard X-ray (HXR) emissions and Doppler velocities caused by the chromospheric evaporation in two X1.6 class solar flares on 2014 September 10 and October 22, respectively. Both events display double…

Solar and Stellar Astrophysics · Physics 2015-11-04 Dong Li , Zongjun Ning , Qingmin Zhang

We explore the effects of electromagnetic (EM) fluctuations in plasmas on solar neutrino fluxes exploiting the fluctuation-dissipation theorem. We find that the EM spectrum in the solar core is enhanced by the EM fluctuations due to the…