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Context. Heating the solar corona to several million degrees requires the conversion of magnetic energy into thermal energy. In this paper, we investigate whether an unstable magnetic thread within a coronal loop can destabilise a…

Solar and Stellar Astrophysics · Physics 2015-07-02 K. V. Tam , A. W. Hood , P. K. Browning , P. J. Cargill

Nanoflares, the basic unit of impulsive energy release may produce much of the solar background emission. Extrapolation of the energy frequency distribution of observed microflares, which follows a power law to lower energies can give an…

Solar and Stellar Astrophysics · Physics 2011-12-22 E. Tajfirouze , H. Safari

We present a detailed analysis of a reflecting intensity perturbation in a large coronal loop that appeared as sloshing oscillation and lasted for at least one and a half periods. The perturbation is initiated by a microflare at one…

Solar and Stellar Astrophysics · Physics 2022-09-14 Fanxiaoyu Xia , Tongjiang Wang , Yang Su , Jie Zhao , Qingmin Zhang , Astrid M. Veronig , Weiqun Gan

Ever since their detection two decades ago, standing kink oscillations in coronal loops have been extensively studied both observationally and theoretically. Almost all driven coronal loop oscillations (e.g., by flares) are observed to damp…

Solar and Stellar Astrophysics · Physics 2019-05-31 C. J. Nelson , A. A. Shukhobodskiy , R. Erdélyi , M. Mathioudakis

The coronal heating problem is one of the most critical challenges in solar physics. Recent observations have revealed that small-scale swirls are ubiquitous in the photosphere and chromosphere, suggesting that they may play a significant…

Solar and Stellar Astrophysics · Physics 2025-08-21 Hidetaka Kuniyoshi , Shinsuke Imada , Takaaki Yokoyama

It is generally agreed that small impulsive energy bursts called nanoflares are responsible for at least some of the Sun's hot corona, but whether they are the explanation for most of the multi-million degree plasma has been a matter of…

Solar and Stellar Astrophysics · Physics 2015-05-28 Sergio Terzo , Fabio Reale , Marco Miceli , James A. Klimchuk , Ryouhei Kano , Saku Tsuneta

The force-free coronal loop model by Titov & D\'emoulin (1999} is found to be unstable with respect to the ideal kink mode, which suggests this instability as a mechanism for the initiation of flares. The long-wavelength ($m=1$) mode grows…

Astrophysics · Physics 2007-05-23 T. Toeroek , B. Kliem , V. S. Titov

The nature and detailed properties of the heating of the million-degree solar corona are important issues that are still largely unresolved. Nanoflare heating might be dominant in active regions and quiet Sun, although direct signatures of…

Context. Nanoflares are small impulsive bursts of energy that blend with and possibly make up much of the solar background emission. Determining their frequency and energy input is central to understanding the heating of the solar corona.…

Astrophysics · Physics 2008-12-20 M. Bazarghan , H. Safari , D. E. Innes , E. Karami , S. K. Solanki

Context: One of the most prominent processes suggested to heat the corona to well above 10^6 K builds on nanoflares, short bursts of energy dissipation. Aims: We compare observations to model predictions to test the validity of the…

Solar and Stellar Astrophysics · Physics 2015-11-04 Leping Li , Hardi Peter , Feng Chen , Jun Zhang

The heating of the solar corona is one of the big questions in astrophysics. Rapid pulses called nanoflares are among the best candidate mechanisms. The analysis of the time variability of coronal X-ray emission is potentially a very useful…

Solar and Stellar Astrophysics · Physics 2012-01-27 S. Terzo , F. Reale , M. Miceli , R. Kano , S. Tsuneta , J. A. Klimchuk

Observations of solar and stellar flares have revealed the presence of power law dependences between the flare energy and the time interval between flares. Various models have been proposed to explain these dependences, and to explain the…

Solar and Stellar Astrophysics · Physics 2018-02-21 D. J. Mullan , R. R. Paudel

We highlight ten key aspects of coronal heating that must be understood before we can consider the problem to be solved. (1) All coronal heating is impulsive. (2) The details of coronal heating matter. (3) The corona is filled with…

Solar and Stellar Astrophysics · Physics 2015-04-13 James A. Klimchuk

The time-dependence of heating in solar active regions can be studied by analyzing the slope of the emission measure distribution cool-ward of the peak. In a previous study we showed that low-frequency heating can account for 0% to 77% of…

Solar and Stellar Astrophysics · Physics 2013-03-20 Jeffrey W. Reep , Stephen J. Bradshaw , James A. Klimchuk

Context. Photospheric motions shuffle the footpoints of the strong axial magnetic field that threads coronal loops giving rise to turbulent nonlinear dynamics characterized by the continuous formation and dissipation of field-aligned…

Solar and Stellar Astrophysics · Physics 2012-08-14 R. B. Dahlburg , G. Einaudi , A. F. Rappazzo , M. Velli

A theory for the heating of coronal magnetic flux ropes is developed. The dissipated magnetic energy has two distinct contributions: (1) energy injected into the corona as a result of granule-scale, random footpoint motions, and (2) energy…

Astrophysics · Physics 2009-11-13 A. A. van Ballegooijen , S. R. Cranmer

Electron ring velocity space distributions have previously been seen in numerical simulations of magnetic reconnection exhausts and have been suggested to be caused by the magnetization of the electron outflow jet by the compressed…

Current analytical and numerical modelling suggest the existence of ubiquitous thin current sheets in the corona that could explain the observed heating requirements. On the other hand, new high resolution observations of the corona…

Solar and Stellar Astrophysics · Physics 2015-06-19 P. Antolin , T. Yokoyama , T. Van Doorsselaere

Even in the absence of resolved flares, the corona is heated to several million degrees. However, despite its importance for the structure, dynamics, and evolution of the solar atmosphere, the origin of this heating remains poorly…

It is known from numerical simulations that thermal conduction along magnetic field lines plays an important role in the evolution of the kink instability in coronal loops. This study presents the observational signatures of the kink…

Solar and Stellar Astrophysics · Physics 2013-03-05 G. J. J. Botha , T. D. Arber , Abhishek K. Srivastava