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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

We analyse transverse oscillations of a coronal loop excited by continuous monoperiodic motions of the loop footpoint at different frequencies in the presence of gravity. Using the MPI-AMRVAC code, we perform three-dimensional numerical…

Solar and Stellar Astrophysics · Physics 2019-05-15 Andrey Afanasyev , Konstantinos Karampelas , Tom Van Doorsselaere

Spicules are thin, elongated jet-like features seen in observations of the solar atmosphere, at the interface between the solar photosphere and the corona. These features exhibit highly complex dynamics and are a necessary connecting link…

Solar and Stellar Astrophysics · Physics 2025-08-04 Sankalp Srivastava , Piyali Chatterjee , Sahel Dey , Robertus Erdélyi

For the first time, we demonstrate how an MHD avalanche might occur in a multi-threaded coronal loop. Considering 23 non-potential magnetic threads within a loop, we use 3D MHD simulations to show that only one thread needs to be unstable…

Solar and Stellar Astrophysics · Physics 2016-01-27 A. W. Hood , P. J. Cargill , P. K. Browning , K. V. Tam

Observational and theoretical evidence suggests that coronal heating is impulsive and occurs on very small cross-field spatial scales. A single coronal loop could contain a hundred or more individual strands that are heated…

Astrophysics · Physics 2009-11-13 J. A. Klimchuk , S. Patsourakos , P. J. Cargill

MHD kink instability can trigger the fragmentation of a twisted magnetic flux tube into small-scale current sheets that dissipate as aperiodic impulsive heating events. This instability propagates as an avalanche to nearby flux tubes and…

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

The periodic coronal rain and in-phase radiative intensity pulsations have been observed in multiple wavelengths in recent years. However, due to the lack of three-dimensional coronal magnetic fields and thermodynamic data in observations,…

Solar and Stellar Astrophysics · Physics 2024-09-02 Zekun Lu , Feng Chen , J. H. Guo , M. D. Ding , Can Wang , Haocheng Yu , Y. W. Ni , Chun Xia

There is increasingly strong observational evidence that slow magnetoacoustic modes arise in the solar atmosphere. Solar magneto-seismology is a novel tool to derive otherwise directly un-measurable properties of the solar atmosphere when…

Solar and Stellar Astrophysics · Physics 2015-06-04 M. Luna-Cardozo , G. Verth , R. Erdélyi

It is clear that the solar corona is being heated and that coronal magnetic fields undergo reconnection all the time. Here we attempt to show that these two facts are in fact related - i.e. coronal reconnection generates heat. This attempt…

Solar and Stellar Astrophysics · Physics 2023-07-19 Dana W. Longcope , Lucas A. Tarr

Most large scale dynamo research for astrophysical rotators focuses on interior flow driven helical dynamos (FDHDs), but larger scale coronal fields most directly influence observations. It is thus important to understand the relationship…

Astrophysics · Physics 2008-11-26 Eric G. Blackman

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

3D simulations of magnetic flux emergence are carried out in a computational domain spanning the upper layers of the convection zone to the lower corona. We use the Oslo Staggered Code to solve the full MHD equations with non-grey and NLTE…

Solar and Stellar Astrophysics · Physics 2009-08-11 J. Martinez-Sykora , V. Hansteen , M. Carlsson

The energy that heats the magnetically closed solar corona originates in the complex motions of the massive photosphere. Turbulent photospheric convection slowly displaces the footpoints of coronal field lines, causing them to become…

The solar wind is connected to the Sun's atmosphere by flux tubes that are rooted in an ever-changing pattern of positive and negative magnetic polarities on the surface. Observations indicate that the magnetic field is filamentary and…

Solar and Stellar Astrophysics · Physics 2015-06-15 Steven R. Cranmer , Adriaan A. van Ballegooijen , Lauren N. Woolsey

There is ample evidence of twisted magnetic structures in the solar corona. This motivates us to consider the magnetic twist as the cause of Alfven frequency continuum in the coronal loops, which can support the resonant absorption as a…

Solar and Stellar Astrophysics · Physics 2016-08-18 Zanyar Ebrahimi , Kayoomars Karami

Recent observations of reflected propagating and standing slow-mode waves in hot flaring coronal loops have spurred our investigation into their underlying excitation and damping mechanisms. To understand these processes, we conduct 2.5D…

Solar and Stellar Astrophysics · Physics 2024-04-01 Tongjiang Wang , Leon Ofman , Stephen J. Bradshaw

We present numerical simulations in 3D settings where coronal rain phenomena take place in a magnetic configuration of a quadrupolar arcade system. Our simulation is a magnetohydrodynamic simulation including anisotropic thermal conduction,…

Solar and Stellar Astrophysics · Physics 2016-01-20 S. P. Moschou , R. Keppens , C. Xia , X. Fang

Coronal holes are the dark patches in the solar corona associated with relatively cool, less dense plasma and unipolar fields. The fast component of the solar wind emanates from these regions. Several observations reveal the presence of…

Solar and Stellar Astrophysics · Physics 2016-03-09 D. Banerjee , S. Krishna Prasad

We aim to identify the physical processes which occur in the magnetic network of the chromosphere and which contribute to its dynamics and heating. Specifically, we study the propagation of transverse (kink) MHD waves which are impulsively…

Astrophysics · Physics 2009-11-10 S. S. Hasan , P. Ulmschneider