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Adopting the MPI-AMRVAC code, we present a 2.5-dimensional magnetohydrodynamic (MHD) simulation, which includes thermal conduction and radiative cooling, to investigate the formation and evolution of the coronal rain phenomenon. We perform…

Solar and Stellar Astrophysics · Physics 2022-03-09 Xiaohong Li , Rony Keppens , Yuhao Zhou

The transport of waves and turbulence beyond the photosphere is central to the coronal heating problem. Turbulence in the quiet solar corona has been modeled on the basis of the nearly incompressible magnetohydrodynamic (NI MHD) theory to…

Solar and Stellar Astrophysics · Physics 2023-01-12 Mehmet Sarp Yalim , Gary P. Zank , Mahboubeh Asgari-Targhi

Coronal loops trace out bipolar, arch-like magnetic fields above the Sun's surface. Recent measurements that combine rotational tomography, extreme ultraviolet imaging, and potential-field extrapolation have shown the existence of large…

Solar and Stellar Astrophysics · Physics 2016-11-15 Avery J. Schiff , Steven R. Cranmer

We explore the suggestions by Uzdensky (2007) and Cassak et al. (2008) that coronal loops heated by magnetic reconnection should self-organize to a state of marginal collisionality. We discuss their model of coronal loop dynamics with a…

Solar and Stellar Astrophysics · Physics 2015-06-05 S. Imada , E. G. Zweibel

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…

We investigate the evolution of coronal loop emission in the context of the coronal magnetic field topology. New modeling techniques allow us to investigate the magnetic field structure and energy release in active regions. Using these…

Solar and Stellar Astrophysics · Physics 2015-05-19 J. -Y. Lee , Graham Barnes , K. D. Leka , Katharine K. Reeves , K. E. Korreck , L. Golub , E. E. DeLuca

The Sun's corona is millions of degrees hotter than its 5,000 K photosphere. This heating enigma is typically addressed by invoking the deposition at coronal heights of non-thermal energy generated by the interplay between convection and…

Solar and Stellar Astrophysics · Physics 2009-08-11 Bart De Pontieu , Scott W. McIntosh , Viggo H. Hansteen , Carolus J. Schrijver

Solar coronal loops are commonly subject to oscillations. Observations of coronal oscillations are used to infer physical properties of the coronal plasma using coronal seismology. Excitation and evolution of oscillations in coronal loops…

Solar and Stellar Astrophysics · Physics 2021-03-17 P. Kohutova , A. Popovas

Coronal heating through the explosive release of magnetic energy remains an open problem in solar physics. Recent hydrodynamical models attempt an investigation by placing swarms of 'nanoflares' at random sites and times in modeled…

Solar and Stellar Astrophysics · Physics 2016-11-30 K. Moraitis , A. Toutountzi , H. Isliker , M. Georgoulis , L. Vlahos , G. Chintzoglou

Twisted coronal loops should be ubiquitous in the solar corona. Twisted magnetic fields contain excess magnetic energy, which can be released during magnetic reconnection, causing solar flares. The aim of this work is to investigate…

Solar and Stellar Astrophysics · Physics 2015-01-27 Mykola Gordovskyy , Philippa Browning , Eduard Kontar , Nicolas Bian

The temperature of the solar atmosphere increases from thousands to millions of degrees moving from the lower layer (chromosphere) to the outermost one (corona), while the density drops accordingly. The mechanism behind this phenomenon,…

Solar and Stellar Astrophysics · Physics 2023-12-27 Luca Barbieri , Lapo Casetti , Andrea Verdini , Simone Landi

Determining the mechanisms responsible for the heating of the coronal plasma and maintaining and accelerating the solar wind are long standing goals in solar physics. There is a clear need to constrain the energy, mass and momentum flux…

Solar and Stellar Astrophysics · Physics 2016-11-21 R. J. Morton , E. Scullion , D. S. Bloomfield , J. A. McLaughlin , S. Regnier , S. W. McIntosh , S. Tomczyk , P. Young

Observed spectral profiles of emission lines from the corona are found to have widths exceeding the thermal line width. To investigate the physical mechanism, we run a 3D MHD model of a single, straightened loop in which we partially…

Solar and Stellar Astrophysics · Physics 2024-04-02 C. A. Breu , H. Peter , S. K. Solanki , R. Cameron , I. De Moortel

Long-time high-resolution simulations of the dynamics of a coronal loop in cartesian geometry are carried out, within the framework of reduced magnetohydrodynamics (RMHD), to understand coronal heating driven by motion of field lines…

Astrophysics · Physics 2008-11-26 A. F. Rappazzo , M. Velli , G. Einaudi , R. B. Dahlburg

The excess temperature of the solar corona over the photosphere poses a challenge. Multiple energetic events contribute to maintaining the corona at such high temperatures. The energy released in different events can vary across several…

Solar and Stellar Astrophysics · Physics 2023-02-21 Abhishek Rajhans

The solar atmosphere is filled with clusters of hot small-scale loops commonly known as Coronal Bright Points (CBPs). These ubiquitous structures stand out in the Sun by their strong X-ray and/or extreme-ultraviolet (EUV) emission for hours…

Solar and Stellar Astrophysics · Physics 2024-06-14 D. Nóbrega-Siverio , F. Moreno-Insertis , K Galsgaard , K. Krikova , L. Rouppe van der Voort , R. Joshi , M. S. Madjarska

Coronal plasma in the cores of solar active regions is impulsively heated to more than 5 MK. The nature and location of the magnetic energy source responsible for such impulsive heating is poorly understood. Using observations of seven…

Solar and Stellar Astrophysics · Physics 2020-12-21 L. P. Chitta , H. Peter , E. R. Priest , S. K. Solanki

Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed…

Solar and Stellar Astrophysics · Physics 2015-05-14 Steven R. Cranmer

Magnetohydrodynamic (MHD) waves and/or the braiding of magnetic field lines are largely thought to be responsible for heating the solar corona, both being mechanisms which are driven by the Sun's photospheric magnetic field. Recent…

The question why the solar corona is much hotter than the visible solar surface still puzzles solar researchers. Most theories of the coronal heating involve a tight coupling between the coronal magnetic field and the associated thermal…

Solar and Stellar Astrophysics · Physics 2021-03-17 Gregory D. Fleishman , Sergey A. Anfinogentov , Alexey G. Stupishin , Alexey A. Kuznetsov , Gelu M. Nita