MHD waves in magnetically twisted solar atmospheric flux tubes

2006 ◽  
Vol 2 (S233) ◽  
pp. 134
Author(s):  
Robert Erdélyi ◽  
Viktor Fedun
Keyword(s):  
Mhd Waves ◽  
Flux Tubes ◽  
Atmospheric Flux

Linear Visco-Resistive Computations of Magnetohydrodynamic Waves: I. The Code and Test Cases

1994 ◽  
Vol 144 ◽  
pp. 503-505
Author(s):  
R. Erdélyi ◽  
M. Goossens ◽  
S. Poedts
Keyword(s):  
Resonant Absorption ◽  
Numerical Code ◽  
Mhd Waves ◽  
Test Cases ◽  
Numerical Accuracy ◽  
Element Discretization ◽  
Flux Tubes ◽  
Magnetohydrodynamic Waves ◽  
Viscosity Coefficients ◽  
Magnetic Flux Tubes

AbstractThe stationary state of resonant absorption of linear, MHD waves in cylindrical magnetic flux tubes is studied in viscous, compressible MHD with a numerical code using finite element discretization. The full viscosity tensor with the five viscosity coefficients as given by Braginskii is included in the analysis. Our computations reproduce the absorption rates obtained by Lou in scalar viscous MHD and Goossens and Poedts in resistive MHD, which guarantee the numerical accuracy of the tensorial viscous MHD code.

Sausage MHD Waves in Incompressible Flux Tubes with Twisted Magnetic Fields

Solar Physics ◽  
2006 ◽  
Vol 238 (1) ◽  
pp. 41-59 ◽  
Author(s):  
Robert Erdélyi ◽  
Viktor Fedun
Keyword(s):  
Magnetic Fields ◽  
Mhd Waves ◽  
Flux Tubes

scholarly journals The Effect of Flow on the Resonance Absorption of Slow MHD Waves in Magnetic Flux Tubes

2021 ◽  
Vol 909 (2) ◽  
pp. 201
Author(s):  
Mohammad Sadeghi ◽  
Karam Bahari ◽  
Kayoomars Karami
Keyword(s):  
Magnetic Flux ◽  
Resonance Absorption ◽  
Mhd Waves ◽  
Flux Tubes ◽  
Magnetic Flux Tubes

scholarly journals Transverse waves in coronal flux tubes with thick boundaries: The effect of longitudinal flows

2019 ◽  
Vol 623 ◽  
pp. A32
Author(s):  
Roberto Soler
Keyword(s):  
Singular Term ◽  
Mhd Waves ◽  
Transverse Waves ◽  
Flux Tubes ◽  
Cascade Energy ◽  
Kink Waves ◽  
Frobenius Series ◽  
The Impact ◽  
The Waves ◽  
Boundary Approximation

Observations show that transverse magnetohydrodynamic (MHD) waves and flows are often simultaneously present in magnetic loops of the solar corona. The waves are resonantly damped in the Alfvén continuum because of plasma and/or magnetic field nonuniformity across the loop. The resonant damping is relevant in the context of coronal heating, since it provides a mechanism to cascade energy down to the dissipative scales. It has been theoretically shown that the presence of flow affects the waves propagation and damping, but most of the studies rely on the unjustified assumption that the transverse nonuniformity is confined to a boundary layer much thinner than the radius of the loop. Here we present a semi-analytic technique to explore the effect of flow on resonant MHD waves in coronal flux tubes with thick nonuniform boundaries. We extend a published method, which was originally developed for a static plasma, in order to incorporate the effect of flow. We allowed the flow velocity to continuously vary within the nonuniform boundary from the internal velocity to the external velocity. The analytic part of the method is based on expressing the wave perturbations in the thick nonuniform boundary of the loop as a Frobenius series that contains a singular term accounting for the Alfvén resonance, while the numerical part of the method consists of solving iteratively the transcendental dispersion relation together with the equation for the Alfvén resonance position. As an application of this method, we investigated the impact of flow on the phase velocity and resonant damping length of MHD kink waves. With the present method, we consistently recover results in the thin boundary approximation obtained in previous studies. We have extended those results to the case of thick boundaries. We also explored the error associated with the use of the thin boundary approximation beyond its regime of applicability.

scholarly journals Nonlinear theory of non-axisymmetric resonant slow waves in straight magnetic flux tubes

2000 ◽  
Vol 64 (5) ◽  
pp. 579-599 ◽  
Author(s):  
I. BALLAI ◽  
R. ERDÉLYI ◽  
M. GOOSSENS
Keyword(s):  
Solar Phys ◽  
Normal Component ◽  
Mhd Equations ◽  
Mhd Waves ◽  
Mean Flow ◽  
Slab Geometry ◽  
Flux Tubes ◽  
Magnetic Flux Tubes ◽  
Field Lines ◽  
Connection Formulae

Nonlinear resonant slow magnetohydrodynamic (MHD) waves are studied in weakly dissipative isotropic plasmas for a cylindrical equilibrium model. The equilibrium magnetic field lines are unidirectional and parallel with the z axis. The nonlinear governing equations for resonant slow magnetoacoustic (SMA) waves are derived. Using the method of matched asymptotic expansions inside and outside the narrow dissipative layer, we generalize the connection formulae for the Eulerian perturbation of the total pressure and for the normal component of the velocity. These nonlinear connection formulae in dissipative cylindrical MHD are an important extention of the connection formulae obtained in linear ideal MHD [Sakurai et al., Solar Phys. 133, 227 (1991)], linear dissipative MHD [Goossens et al., Solar Phys. 175, 75 (1995); Erdélyi, Solar Phys. 171, 49 (1997)] and in nonlinear dissipative MHD derived in slab geometry [Ruderman et al., Phys. Plasmas4, 75 (1997)]. These generalized connection formulae enable us to connect the solutions at both sides of the dissipative layer without solving the MHD equations in the dissipative layer. We also show that the nonlinear interaction of harmonics in the dissipative layer is responsible for generating a parallel mean flow outside the dissipative layer.

MHD Waves in Coronal Flux Tubes

1994 ◽  
pp. 121-124
Author(s):  
J. P. Goedbloed ◽  
G. Halberstadt
Keyword(s):  
Mhd Waves ◽  
Flux Tubes

MHD Waves in Magnetic Flux Tubes

1996 ◽  
pp. 61-83 ◽  
Author(s):  
Marcel Goossens ◽  
Michael Ruderman
Keyword(s):  
Magnetic Flux ◽  
Mhd Waves ◽  
Flux Tubes ◽  
Magnetic Flux Tubes

scholarly journals GENERATION OF MAGNETOHYDRODYNAMIC WAVES IN LOW SOLAR ATMOSPHERIC FLUX TUBES BY PHOTOSPHERIC MOTIONS

2015 ◽  
Vol 799 (1) ◽  
pp. 6 ◽  
Author(s):  
S. J. Mumford ◽  
V. Fedun ◽  
R. Erdélyi
Keyword(s):  
Flux Tubes ◽  
Magnetohydrodynamic Waves ◽  
Atmospheric Flux

Resonant behaviour of MHD waves on magnetic flux tubes

Solar Physics ◽  
1991 ◽  
Vol 133 (2) ◽  
pp. 247-262 ◽  
Author(s):  
Takashi Sakurai ◽  
Marcel Goossens ◽  
Joseph V. Hollweg
Keyword(s):  
Magnetic Flux ◽  
Mhd Waves ◽  
Flux Tubes ◽  
Magnetic Flux Tubes
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