相关论文: Direct Imaging of Magnetohydrodynamic Wave Mode Co…
Mode conversion occurs when a wave passes through a region where the sound and Alfven speeds are equal. At this point there is a resonance, which allows some of the incident wave to be converted into a different mode. We study this…
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…
We present a new MHD wave decomposition method that overcomes the limitations of existing wave identification methods. Our method allows to investigate the energy fluxes in different MHD modes at different locations of the solar atmosphere…
The solar atmosphere is known to contain many different types of wavelike oscillation. Waves and other fluctuations (e.g., turbulent eddies) are believed to be responsible for at least some of the energy transport and dissipation that heats…
The efficacy of fast/slow MHD mode conversion in the surface layers of sunspots has been demonstrated over recent years using a number of modelling techniques, including ray theory, perturbation theory, differential eigensystem analysis,…
We investigate the viability of MHD waves, in particular acoustic p-modes, in causing strong current accumulation at the null points. We begin with a three-dimensional numerical setup incorporating a gravitationally stratifed solar…
We perform nonlinear MHD simulations to study the propagation of magnetoacoustic waves from the photosphere to the low corona. We focus on a 2D system with a gravitationally stratified atmosphere and three photospheric concentrations of…
Context: Coronal magnetic null points have been implicated as possible locations for localised heating events in 2D models. We investigate this possibility about fully 3D null points. Aims: We investigate the nature of the fast…
The nature of fast magnetoacoustic and Alfv\'en waves is investigated in a zero $\beta$ plasma in the neighbourhood of a pair of two-dimensional null points. This gives an indication of wave propagation in the low $\beta$ solar corona, for…
The nature of fast magnetoacoustic and Alfv\'en waves is investigated in a zero $\beta$ plasma. This gives an indication of wave propagation in the low $\beta$ solar corona. It is found that for a two-dimensional null point, the fast wave…
Identifying the heating mechanisms of the solar corona and the driving mechanisms of solar wind are key challenges in understanding solar physics. A full three-dimensional compressible magnetohydrodynamic (MHD) simulation was conducted to…
Magnetohydrodynamic (MHD) waves are candidates for heating the solar chromosphere, although it is still unclear which mode of the wave is dominant in heating. We perform two-dimensional radiative MHD simulation to investigate the…
An enhancement in high-frequency acoustic power is commonly observed in the solar photosphere and chromosphere surrounding magnetic active regions. We perform 3D linear forward wave modelling with a simple wavelet pulse acoustic source to…
Sunspots are intense regions of magnetic flux that are rooted deep below the photosphere. It is well established that sunspots host magnetohydrodynamic waves, with numerous observations showing a connection to the internal acoustic (or…
A 2.5D numerical model of magnetoacoustic-Alfv\'en linear mode conversions in the partially ionised low solar atmosphere induced by the Hall effect is surveyed, varying magnetic field strength and inclination, and wave frequency and…
This paper is a demonstration of how the WKB approximation can be used to help solve the linearised 3D MHD equations. Using Charpit's Method and a Runge-Kutta numerical scheme, we have demonstrated this technique for a potential 3D magnetic…
Context: MHD waves and magnetic null points are both prevalent in many astrophysical plasmas, including the solar atmosphere. Interaction between waves and null points has been implicated as a possible mechanism for localised heating…
We present a new global model of the solar corona, including the low corona, the transition region and the top of chromosphere. The realistic 3D magnetic field is simulated using the data from the photospheric magnetic field measurements.…
Recent numerical investigations of wave propagation near coronal magnetic null points (McLaughlin and Hood: Astron. Astrophys. 459, 641,2006) have indicated how a fast MHD wave partially converts into a slow MHD wave as the disturbance…
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…