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Related papers: Can Thermal Nonequilibrium Explain Coronal Loops?

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Observations of coronal loops have identified several common loop characteristics, including that loops appear to cool and have higher than expected densities. Two potential heating scenarios have been suggested to explain these…

Solar and Stellar Astrophysics · Physics 2018-10-03 Amy R. Winebarger , Roberto Lionello , Cooper Downs , Zoran Mikic , Jon Linker

Due to their characteristic temperature and density, loop structures in active regions (ARs) can be seen bright in extreme ultraviolet (EUV) and soft X-ray images. The semiempirical determination of the three-dimensional (3D) distribution…

Solar and Stellar Astrophysics · Physics 2020-12-16 F. A. Nuevo , C. Mac Cormack , M. López Fuentes , A. M. Vásquez , C. H. Mandrini

We study a series of relations between physical parameters in coronal loops of the quiet Sun reconstructed by combining tomographic techniques and modeling of the coronal magnetic field. We use differential emission measure tomography…

Solar and Stellar Astrophysics · Physics 2022-06-22 C. Mac Cormack , M. López Fuentes , C. H. Mandrini , D. G. Lloveras , M. Poisson , A. M. Vásquez

We perform MHD modeling of a single bright coronal loop to include the interaction with a non-uniform magnetic field. The field is stressed by random footpoint rotation in the central region and its energy is dissipated into heating by…

Solar and Stellar Astrophysics · Physics 2016-10-12 F. Reale , S. Orlando , M. Guarrasi , A. Mignone , G. Peres , A. W. Hood , E. R. Priest

We report on the properties of coronal loop foot-point heating with observations at the highest resolution, from the CRisp Imaging Spectro-Polarimeter (CRISP) located at the Swedish 1-m Solar Telescope (SST) and co-aligned NASA Solar…

Solar and Stellar Astrophysics · Physics 2021-11-24 V. N. Nived , E. Scullion , J. G. Doyle , R. Susino , P. Antolin , D. Spadaro , C. Sasso , S. Sahin , M. Mathioudakis

We have measured line widths in active region coronal loops in order to determine whether the non-thermal broadening is anisotropic with respect to the magnetic field direction. These non-thermal velocities are caused by unresolved fluid…

Solar and Stellar Astrophysics · Physics 2023-08-09 Michael Hahn , Mahboubeh Asgari-Targhi , Daniel Wolf Savin

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 heating of the solar chromosphere and corona to the observed high temperatures, imply the presence of ongoing heating that balances the strong radiative and thermal conduction losses expected in the solar atmosphere. It has been…

The heating of the Sun's corona has been explained by several different mechanisms including wave dissipation and magnetic reconnection. While both have been shown capable of supplying the requisite power, neither has been used in a…

Solar and Stellar Astrophysics · Physics 2018-02-20 Kai E. Yang , Dana W. Longcope , M. D. Ding , Yang Guo

The tropical wisdom that when it is hot and dense we can expect rain might also apply to the Sun. Indeed, observations and numerical simulations have shown that strong heating at footpoints of loops, as is the case for active regions, puts…

Solar and Stellar Astrophysics · Physics 2012-02-06 P. Antolin , M. Carlsson , L. Rouppe van der Voort , E. Verwichte , G. Vissers

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

Rapidly decaying long-period oscillations often occur in hot coronal loops of active regions associated with small (or micro-) flares. This kind of wave activity was first discovered with the SOHO/SUMER spectrometer from Doppler velocity…

Solar and Stellar Astrophysics · Physics 2021-10-01 Tongjiang Wang , Leon Ofman , Ding Yuan , Fabio Reale , Dmitrii Y. Kolotkov , Abhishek K. Srivastava

We present the results of 1D hydrodynamic simulations of coronal loops which are subject to nanoflares, caused by either in-situ thermal heating, or non-thermal electrons (NTE) beams. The synthesized intensity and Doppler shifts can be…

Solar and Stellar Astrophysics · Physics 2018-04-18 V. Polito , P. Testa , J. Allred , B. De Pontieu , M. Carlsson , T. M. D. Pereira , M. Gošić , F. Reale

2.5-dimensional magnetohydrodynamic (MHD) simulations are performed with high spatial resolution in order to distinguish between competing models of the coronal heating problem. A single coronal loop powered by Alfv\'{e}n waves excited in…

Solar and Stellar Astrophysics · Physics 2016-08-24 Takuma Matsumoto

We present the first multidimensional, magnetohydrodynamic simulations which capture the initial formation and the long-term sustainment of the enigmatic coronal rain phenomenon. We demonstrate how thermal instability can induce a…

Solar and Stellar Astrophysics · Physics 2015-06-16 X. Fang , C. Xia , R. Keppens

We perform direct numerical simulations of an externally driven two-dimensional magnetohydrodynamic system over extended periods of time to simulate the dynamics of a transverse section of a solar coronal loop. A stationary and large-scale…

Astrophysics · Physics 2009-10-30 Pablo Dmitruk , Daniel O. Gomez

Cool, dense material is frequently observed to permeate the hot, tenuous solar corona in the form of prominences, spicules and coronal rain. Both the cool material and surrounding corona exist at temperatures that are effectively thermally…

Solar and Stellar Astrophysics · Physics 2026-01-30 B. Snow , A. Hillier

Studying coronal rain formation through thermal non-equilibrium (TNE) and thermal instability (TI) provides insights into coronal heating mechanisms. We analysed a quiescent coronal rain event using space-based observations from the…

Solar and Stellar Astrophysics · Physics 2026-04-08 Jamal Wachira , Patrick Antolin

The solar corona produces coronal rain, hundreds of times colder and denser material than the surroundings. Coronal rain is known to be deeply linked to coronal heating, but its origin, dynamics, and morphology are still not well…

Solar and Stellar Astrophysics · Physics 2023-07-05 Seray Şahin , Patrick Antolin , Clara Froment , Thomas A. Schad

Coronal loops are the basic building block of the upper solar atmosphere. Comprehending how these are energized, structured, and evolve is key to understanding stellar coronae. Here we investigate how the energy to heat the loop is…

Solar and Stellar Astrophysics · Physics 2022-02-09 C. Breu , H. Peter , R. Cameron , S. K. Solanki , D. Przybylski , M. Rempel , L. P. Chitta