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We employ a sequence of Doppler images obtained with the Coronal Multi-channel Polarimeter (CoMP) instrument to perform time-distance seismology of the solar corona. We construct the first k-omega diagrams of the region. These allow us to…

Solar and Stellar Astrophysics · Physics 2010-01-15 Steven Tomczyk , Scott W. McIntosh

A 3D model intermediate between cellular automata (CA) models and the reduced magnetohydrodynamic (RMHD) equations is presented to simulate solar impulsive events generated along a coronal magnetic loop. The model consists of a set of…

Astrophysics · Physics 2007-05-23 E. Buchlin , V. Aletti , S. Galtier , M. Velli , G. Einaudi , J. -C. Vial

One of the leading hypotheses for sunquake generation suggests that flare-accelerated particles originating from the reconnection site in the corona travel down to the chromosphere and photosphere, where they deposit energy through…

Solar and Stellar Astrophysics · Physics 2025-09-09 John Stefan , Alexander Kosovichev

Propagating (intensity) disturbances (PDs) are well reported in observations of coronal loops and polar plumes in addition to recent links with co-temporal spicule activity in the solar atmosphere. However, despite being reported in…

Solar and Stellar Astrophysics · Physics 2024-09-11 Samuel Skirvin , Tanmoy Samanta , Tom Van Doorsselaere

It is extremely difficult to simulate the details of coronal heating and also make meaningful predictions of the emitted radiation. Thus, testing realistic models with observations is a major challenge. Observational signatures of coronal…

Solar and Stellar Astrophysics · Physics 2022-11-02 James A. Klimchuk , Kalman J. Knizhnik , Vadim M. Uritsky

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

Magnetic energy released in the corona by solar flares reaches the chromosphere where it drives characteristic upflows and downflows known as evaporation and condensation. These flows are studied here for the case where energy is…

Solar and Stellar Astrophysics · Physics 2015-06-22 D. W. Longcope

Macroscopic wave and oscillatory phenomena ubiquitously detected in the plasma of the corona of the Sun are interpreted in terms of magnetohydrodynamic theory. Fast and slow magnetoacoustic waves are clearly distinguished in observations.…

Solar and Stellar Astrophysics · Physics 2024-04-02 Valery M. Nakariakov , Sihui Zhong , Dmitrii Y. Kolotkov , Rebecca L. Meadowcroft , Yu Zhong , Ding Yuan

We investigate the propagation of MHD waves in a homogenous, magnetized plasma in a weakly stratified atmosphere, representing hot coronal loops. In most of earlier studies a time-independent equilibrium is considered. Here we abandon this…

Solar and Stellar Astrophysics · Physics 2015-05-20 R. Erdelyi , K. S. Al-Ghafri , R. J. Morton

The highly dynamical, complex nature of the solar atmosphere naturally implies the presence of waves in a topologically varied magnetic environment. Here, the interaction of waves with topological features such as null points is inevitable…

Solar and Stellar Astrophysics · Physics 2015-06-04 J. W. Threlfall , C. E. Parnell , I. De Moortel , K. G. McClements , T. D. Arber

The heating of the lower solar corona is examined using numerical simulations and theoretical models of magnetohydrodynamic turbulence in open magnetic regions. A turbulent energy cascade to small length scales perpendicular to the mean…

Astrophysics · Physics 2009-11-07 P. Dmitruk , W. H. Matthaeus , L. J. Milano , S. Oughton , G. P. Zank , D. J. Mullan

We investigate the effects of interactions between ions and neutrals on the chromosphere and overlying corona using 2.5D radiative MHD simulations with the Bifrost code. We have extended the code capabilities implementing ion-neutral…

Data from recent numerical simulations of the solar corona and transition region are analysed and the magnetic field connection between the low corona and the photosphere is found to be close to that of a potential field. The fieldline to…

Astrophysics · Physics 2014-10-13 B. V. Gudiksen , Å. Nordlund

This work consists of two parts: the first devoted to the study of the heating of the magnetically confined Solar Corona, and the second to the acceleration of the Slow Solar Wind. Direct 3D reduced MHD simulations are presented. They model…

Solar and Stellar Astrophysics · Physics 2010-01-13 A. F. Rappazzo

The chromosphere of the quiet Sun is a highly intermittent and dynamic phenomenon. Three-dimensional radiation (magneto-)hydrodynamic simulations exhibit a mesh-like pattern of hot shock fronts and cool expanding post-shock regions in the…

Astrophysics · Physics 2009-11-13 Sven Wedemeyer-Böhm , Friedrich Wöger

Being directly observed in the Doppler shift and imaging data and indirectly as quasi-periodic pulsations in solar and stellar flares, slow magnetoacoustic waves offer an important seismological tool for probing many vital parameters of the…

Solar and Stellar Astrophysics · Physics 2022-05-25 Dmitrii Y. Kolotkov , Valery M. Nakariakov

We present a comprehensive review of MHD wave behaviour in the neighbourhood of coronal null points: locations where the magnetic field, and hence the local Alfven speed, is zero. The behaviour of all three MHD wave modes, i.e. the Alfven…

Solar and Stellar Astrophysics · Physics 2012-04-30 J. A. McLaughlin , A. W. Hood , I. De Moortel

There have been several ideas proposed to explain how the Sun's corona is heated and how the solar wind is accelerated. Some models assume that open magnetic field lines are heated by Alfven waves driven by photospheric motions and…

Solar and Stellar Astrophysics · Physics 2015-06-22 Steven R. Cranmer

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

The solar surface is a continuous source of internal gravity waves (IGWs). IGWs are believed to supply the bulk of the wave energy for the lower solar atmosphere, but their existence and role for the energy balance of the upper layers is…

Solar and Stellar Astrophysics · Physics 2021-01-20 G. Vigeesh , M. Roth , O. Steiner , B. Fleck