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A major coronal heating theory based on magnetic reconnection relies on the existence of braided magnetic field structures in the corona. In this small-angle reconnection scenario, numerical simulations indicate that the reconnected…

Solar and Stellar Astrophysics · Physics 2024-01-17 A. Ramada. C. Sukarmadji , Patrick Antolin

Context : We present a self-consistent model of solar coronal heating, originally developed by Heyvaert & Priest (1992), in which we include the dynamical effect of the background magnetic field along a coronal structure by using exact…

Astrophysics · Physics 2009-11-13 B. Bigot , S. Galtier , H. Politano

One scenario proposed to explain the million degrees solar corona is a finely-stranded corona where each strand is heated by a rapid pulse. However, such fine structure has neither been resolved through direct imaging observations nor…

Solar and Stellar Astrophysics · Physics 2015-05-28 Fabio Reale , Massimiliano Guarrasi , Paola Testa , Edward E. DeLuca , Giovanni Peres , Leon Golub

We study a 2D cellular automaton (CA) model for the evolution of coronal loop plasmas. The model is based on the idea that coronal loops are made of elementary magnetic strands that are tangled and stressed by the displacement of their…

Solar and Stellar Astrophysics · Physics 2017-03-22 Marcelo López Fuentes , James A. Klimchuk

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

We present a model of magnetohydrodynamic (MHD) turbulence in the extended solar corona that contains the effects of collisionless dissipation and anisotropic particle heating. Measurements made by UVCS/SOHO have revived interest in the…

Astrophysics · Physics 2009-11-07 S. R. Cranmer , A. A. van Ballegooijen

The effect of the numerical spatial resolution in models of the solar corona and corona / chromosphere interface is examined for impulsive heating over a range of magnitudes using one dimensional hydrodynamic simulations. It is demonstrated…

Solar and Stellar Astrophysics · Physics 2015-06-15 Stephen J. Bradshaw , Peter J. Cargill

Kelvin-Helmholtz {instability induced} turbulence is one promising mechanism by which loops in the solar corona can be heated by MHD waves. In this paper we present an analytical model of the dissipation rate of {Kelvin-Helmholtz…

Solar and Stellar Astrophysics · Physics 2020-07-20 Andrew Hillier , Tom Van Doorsselaere , Konstantinos Karampelas

Recently using Particle-In-Cell simulations i.e. in the kinetic plasma description Tsiklauri et al. and G\'enot et al. reported on a discovery of a new mechanism of parallel electric field generation, which results in electron acceleration.…

Astrophysics · Physics 2007-05-23 David Tsiklauri

Recent observational and numerical studies show a variety of thermal structures in the solar chromosphere. Given that the thermal interplay across the transition region is a key to coronal heating, it is worth investigating how different…

Solar and Stellar Astrophysics · Physics 2022-10-26 Haruka Washinoue , Munehito Shoda , Takeru K. Suzuki

Quasi-periodic propagating intensity disturbances have been observed in large coronal loops in EUV images over a decade, and are widely accepted to be slow magnetosonic waves. However, spectroscopic observations from Hinode/EIS revealed…

Solar and Stellar Astrophysics · Physics 2015-11-04 X. Fang , D. Yuan , T. Van Doorsselaere , R. Keppens , C. Xia

There is a growing body of evidence that the plasma loops seen with current instrumentation (SOHO, TRACE and Hinode) may consist of many sub-resolution elements or strands. Thus, the overall plasma evolution we observe in these features…

Astrophysics · Physics 2009-11-13 Aveek Sarkar , Robert W Walsh

Determining the preferred spatial location of the energy input to solar coronal loops would be an important step forward towards a more complete understanding of the coronal heating problem. Following on from Sarkar & Walsh (2008) this…

Solar and Stellar Astrophysics · Physics 2009-07-22 Aveek Sarkar , Robert W Walsh

Context. We have conducted a 3D MHD simulation of the solar corona above an active region (AR) in full scale and high resolution, which shows coronal loops, and plasma flows within them, similar to observations. Aims. We want to find the…

Solar and Stellar Astrophysics · Physics 2017-09-19 Philippe-A. Bourdin , Sven Bingert , Hardi Peter

The heating of coronal loops is investigated to understand the observational consequences in terms of the thermodynamics and radiative losses from the Sun as well as the magnetized coronae of stars with an outer convective envelope. The…

Solar and Stellar Astrophysics · Physics 2018-07-02 A. F. Rappazzo , R. B. Dahlburg , G. Einaudi , M. Velli

We solve numerically ideal, 2.5D, MHD equations in Cartesian coordinates, with a plasma beta of 0.0001 starting from the equilibrium that mimics a footpoint of a large curvature radius solar coronal loop or a polar region plume. On top of…

Astrophysics · Physics 2007-05-23 David Tsiklauri

The existence of the million-degree corona above the cooler photosphere is an unsolved problem in astrophysics. Detailed study of quiescent corona that exists regardless of the phase of the solar cycle may provide fruitful hints towards…

Solar and Stellar Astrophysics · Physics 2022-12-07 Vishal Upendran , Durgesh Tripathi , N. P. S. Mithun , Santosh Vadawale , Anil Bhardwaj

This work analyzes the Hall magnetohydrodynamics (HMHD) and magnetohydrodynamics (MHD) numerical simulations of a flaring solar active region as a testbed while idealizing the coronal Alfv\'en speed to be of two orders of magnitude lesser.…

Solar and Stellar Astrophysics · Physics 2022-02-16 Kamlesh Bora , Ramit Bhattacharyya , Avijeet Prasad , Bhuwan Joshi , Qiang Hu

Recent observations of fast and bursty ``nanojets'' suggest novel diagnostics of nanoflare heating in the solar corona. The aim of this work is to investigate the presence and properties of reconnection outflows, similar to observed…

Solar and Stellar Astrophysics · Physics 2025-11-13 Gabriele Cozzo , Paola Testa , Juan Martinez-Sykora , Paolo Pagano , Fabio Reale , Franco Rappazzo , Viggo Hansteen , Bart De Pontieu

Any successful model of coronal loops must explain a number of observed properties. For warm (~ 1 MK) loops, these include: 1. excess density, 2. flat temperature profile, 3. super-hydrostatic scale height, 4. unstructured intensity…

Solar and Stellar Astrophysics · Physics 2014-11-20 J. A. Klimchuk , J. T. Karpen , S. K. Antiochos