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A compact X-class flare on 2004-Feb-26 showed a concentrated source of hard X-rays at the tops of the flare's loops. This was analyzed in previous work (Longcope et al. 2010), and interpreted as plasma heated and compressed by slow…

Solar and Stellar Astrophysics · Physics 2016-12-28 Dana Longcope , Jiong Qiu , Jasmine Brewer

We present a quantitative model of the magnetic energy stored and then released through magnetic reconnection for a flare on 26 Feb 2004. This flare, well observed by RHESSI and TRACE, shows evidence of non-thermal electrons only for a…

Solar and Stellar Astrophysics · Physics 2011-06-21 D. W. Longcope , A. C. Des Jardins , T. Carranza-Fulmer , J. Qiu

Aspects of solar flare dynamics, such as chromospheric evaporation and flare light-curves, have long been studied using one-dimensional models of plasma dynamics inside a static flare loop, subjected to some energy input. While extremely…

Solar and Stellar Astrophysics · Physics 2015-11-11 Dana Longcope , Jim Klimchuk

We present a novel model in which shortening of a magnetic flux tube following localized, three-dimensional reconnection generates strong gas-dynamic shocks around its apex. The shortening releases magnetic energy by progressing away from…

Astrophysics · Physics 2009-11-13 D. W. Longcope , S. E. Guidoni , M. G. Linton

We show, through a simple patchy reconnection model, that retracting reconnected flux tubes may present elongated regions relatively devoid of plasma, as well as long lasting, dense central hot regions. Reconnection is assumed to happen in…

Solar and Stellar Astrophysics · Physics 2015-05-27 S. E. Guidoni , D. W. Longcope

Magnetic reconnection is a process whereby magnetic field lines in different directions "reconnect" with each other, resulting in the rearrangement of magnetic field topology together with the conversion of magnetic field energy into the…

A soft X-ray enhancement has recently been reported toward the high-velocity cloud MS30.7-81.4-118 (MS30.7), a constituent of the Magellanic Stream. In order to investigate the origin of this enhancement, we have analyzed two overlapping…

Astrophysics of Galaxies · Physics 2015-06-22 David B. Henley , Robin L. Shelton , Kyujin Kwak

Twisted magnetic fields should be ubiquitous in flare-producing active regions where the magnetic fields are strongly non-potential. It has been shown that reconnection in helical magnetic coronal loops results in plasma heating and…

Solar and Stellar Astrophysics · Physics 2016-01-20 R. F. Pinto , M. Gordovskyy , P. K. Browning , N. Vilmer

Nonthermal loop-top sources in solar flares are the most prominent observational signature that suggests energy release and particle acceleration in the solar corona. Although several scenarios for particle acceleration have been proposed,…

Solar and Stellar Astrophysics · Physics 2020-01-08 Xiangliang Kong , Fan Guo , Chengcai Shen , Bin Chen , Yao Chen , Sophie Musset , Lindsay Glesener , Peera Pongkitiwanichakul , Joe Giacalone

Magnetic reconnection drives a wide range of astrophysical plasma phenomena, including solar flares, by converting magnetic energy into plasma energy through changes in magnetic field topology. Petschek reconnection is a magnetohydrodynamic…

Solar and Stellar Astrophysics · Physics 2026-04-01 Keita Akutagawa , Shinsuke Imada , Munehito Shoda

Recent numerical simulations of magnetic reconnection in two dimensions have shown that, when the resistivity is strongly localized, the reconnection region develops a Petschek-like structure, with the width of the inner diffusion region…

Astrophysics · Physics 2009-11-07 Dmitri A. Uzdensky

We present data analysis and interpretation of a simple X-class flare observed with RHESSI on November 3, 2003. In contrast to other X-class flares observed previously, this flare shows a very simple morphology with well defined looptop…

Astrophysics · Physics 2009-11-10 Wei Liu , Yan Wei Jiang , Siming Liu , Vahe' Petrosian

In models of fast magnetic reconnection, flux transfer occurs within a small portion of a current sheet triggering stored magnetic energy to be thermalized by shocks. When the initial current sheet separates magnetic fields which are not…

Solar and Stellar Astrophysics · Physics 2015-05-19 D. W. Longcope , S. J. Bradshaw

The interrelation of hard X-ray (HXR) emitting sources and the underlying physics of electron acceleration and transport presents one of the major questions in high-energy solar flare physics. Spatially resolved observations of solar flares…

Solar and Stellar Astrophysics · Physics 2015-06-12 Paulo J. A. Simões , Eduard P. Kontar

Using a recently developed analytical procedure, we determine the rate of magnetic reconnection in the "standard" model of eruptive solar flares. During the late phase, the neutral line is located near the lower tip of the reconnection…

Solar and Stellar Astrophysics · Physics 2018-05-23 Terry G. Forbes , Daniel B. Seaton , Katharine K. Reeves

This paper reports on the re-analysis of solar flares in which the hard X-rays (HXRs) come predominantly from the corona rather than from the more usual chromospheric footpoints. All of the 26 previously analyzed event time intervals, over…

Solar and Stellar Astrophysics · Physics 2018-11-07 Brian R. Dennis , Miguel A. Duval-Poo , Michele Piana , Andrew R. Inglis , A. Gordon Emslie , Jingnan Guo , Yan Xu

The acceleration and transport of energetic electrons during solar flares is one of the outstanding topics in solar physics. Recent X-ray and radio imaging and spectroscopy observations have provided diagnostics of the distribution of…

Solar and Stellar Astrophysics · Physics 2022-12-21 Xiangliang Kong , Bin Chen , Fan Guo , Chengcai Shen , Xiaocan Li , Jing Ye , Lulu Zhao , Zelong Jiang , Sijie Yu , Yao Chen , Joe Giacalone

A fast-mode shock can form in the front of reconnection outflows and has been suggested as a promising site for particle acceleration in solar flares. Recent development of magnetic reconnection has shown that numerous plasmoids can be…

Solar and Stellar Astrophysics · Physics 2022-05-25 Xiangliang Kong , Fan Guo , Chengcai Shen , Bin Chen , Yao Chen , Joe Giacalone

Solar flares are accompanied by an enhanced emission of electromagnetic waves from the radio up to the gamma-ray range. The associated hard X-ray (HXR) and microwave radiation is generated by energetic electrons, which carry a substantial…

Solar and Stellar Astrophysics · Physics 2024-04-19 G. Mann , A. M. Veronig , F. Schuller

Magnetic reconnection at small spatial scales is a fundamental driver of energy release and plasma dynamics in the lower solar atmosphere. We present observations of a brightening in an active region, captured in high-resolution data from…

Solar and Stellar Astrophysics · Physics 2025-04-14 J. M. da Silva Santos , E. Dunnington , R. Jarolim , S. Danilovic , S. Criscuoli
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