Numerical simulations of the lower solar atmosphere heating by two-fluid nonlinear Alfvén waves

Context. We present new insight into the long-standing problem of plasma heating in the lower solar atmosphere in terms of collisional dissipation caused by two-fluid Alfvén waves. Aims. Using numerical simulations, we study Alfvén wave propagation and dissipation in a magnetic flux tube and their heating effect. Methods. We set up 2.5-dimensional numerical simulations with a semi-empirical model of a stratified solar atmosphere and a force-free magnetic field mimicking a magnetic flux tube. We consider a partially ionized plasma consisting of ion + electron and neutral fluids, which are coupled by ion-neutral collisions. Results. We find that Alfvén waves, which are directly generated by a monochromatic driver at the bottom of the photosphere, experience strong damping. Low-amplitude waves do not thermalize sufficient wave energy to heat the solar atmospheric plasma. However, Alfvén waves with amplitudes greater than 0.1 km s−1 drive through ponderomotive force magneto-acoustic waves in higher atmospheric layers. These waves are damped by ion-neutral collisions, and the thermal energy released in this process leads to heating of the upper photosphere and the chromosphere. Conclusions. We infer that, as a result of ion-neutral collisions, the energy carried initially by Alfvén waves is thermalized in the upper photosphere and the chromosphere, and the corresponding heating rate is large enough to compensate radiative and thermal-conduction energy losses therein.

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On vertical spinning Alfvén waves in a magnetic flux tube

Journal of Plasma Physics ◽

10.1017/s0022377800016664 ◽

1992 ◽

Vol 48 (3) ◽

pp. 415-434 ◽

Cited By ~ 17

Author(s):

L. M. B. C. Campos ◽

N. L. Isaeva

Keyword(s):

Magnetic Field ◽

Exact Solution ◽

Magnetic Flux ◽

Hall Effect ◽

Flux Tube ◽

Critical Level ◽

Alfven Waves ◽

Second Order ◽

Magnetic Flux Tube ◽

Alfvén Waves

We derive the Alfvén-wave equation for an atmosphere in the presence of a non-uniform vertical magnetic field and the Hall effect, allowing for Alfvén speed and ion gyrofrequency that may vary with altitude; the pair of coupled second-order differential equations for the horizontal wave variables, namely magnetic field or velocity perturbations, is reduced to a single complex, second-order differential equation. The latter is applied to spinning Alfvén waves in a magnetic flux tube, in magnetohydrostatic equilibrium, in an isothermal atmosphere. The exact solution is found in terms of hypergeometric functions, from which it is shown that at ‘high altitude’the magnetic field perturbation tends to grow to a non-small fraction of the background magnetic field. By ‘high-altitude’ is meant far above the critical level, which acts as a reflecting layer for left-polarized waves incident from below, i.e. from the ‘low-altitude’ range. We also obtain the exact solution near the critical level, where the left-polarized wave has a logarithmic singularity, and the right-polarized wave is finite. The latter is plotted in this region of wave frequency comparable to ion gyrofrequency, and it is shown that the Hall effect can cause oscillations of wave amplitude and non-monotonic phases with slope of alternating sign. The latter corresponds to ‘tunnelling’, i.e. waves propagating in opposite directions or trapped in adjoining atmospheric layers; this could explain the appearance of inward- and outward-propagating waves, with almost random phases, in the solar wind beyond the earth, for which the Hall effect on Alfvén waves should be significant.

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Simulation of a Collision between Shock Waves and a Magnetic Flux Tube: Excitation of Surface Alfven Waves and Body Alfven Waves

The Astrophysical Journal ◽

10.1086/309064 ◽

2000 ◽

Vol 537 (2) ◽

pp. 1063-1072 ◽

Cited By ~ 29

Author(s):

J. I. Sakai ◽

T. Kawata ◽

K. Yoshida ◽

K. Furusawa ◽

N. F. Cramer

Keyword(s):

Shock Waves ◽

Magnetic Flux ◽

Flux Tube ◽

Alfven Waves ◽

Magnetic Flux Tube ◽

Alfvén Waves

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MHD waves generated by high-frequency photospheric vortex motions

Annales Geophysicae ◽

10.5194/angeo-29-1029-2011 ◽

2011 ◽

Vol 29 (6) ◽

pp. 1029-1035 ◽

Cited By ~ 43

Author(s):

V. Fedun ◽

S. Shelyag ◽

G. Verth ◽

M. Mathioudakis ◽

R. Erdélyi

Keyword(s):

Magnetic Flux ◽

Solar Atmosphere ◽

Flux Tube ◽

High Frequency ◽

Three Dimensional ◽

Mhd Waves ◽

Magnetic Flux Tube ◽

Open Magnetic Flux ◽

Cartesian Coordinate ◽

Lower Solar Atmosphere

Abstract. In this paper, we discuss simulations of MHD wave generation and propagation through a three-dimensional open magnetic flux tube in the lower solar atmosphere. By using self-similar analytical solutions for modelling the magnetic field in Cartesian coordinate system, we have constructed a 3-D magnetohydrostatic configuration which is used as the initial condition for non-linear MHD wave simulations. For a driver we have implemented a high-frequency vortex-type motion at the footpoint region of the open magnetic flux tube. It is found that the implemented swirly source is able to excite different types of wave modes, i.e. sausage, kink and torsional Alfvén modes. Analysing these waves by magneto-seismology tools could provide insight into the magnetic structure of the lower solar atmosphere.

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Estimation of the Energy Flux of Torsional Alfvén Waves in the Lower Solar Atmosphere Based on Measurements of the Doppler Velocities

Geomagnetism and Aeronomy ◽

10.1134/s0016793221070197 ◽

2021 ◽

Vol 61 (7) ◽

pp. 1035-1037

Author(s):

Yu. T. Tsap ◽

A. V. Stepanov ◽

Yu. G. Kopylova ◽

O. V. Khaneychuk ◽

T. B. Goldvarg

Keyword(s):

Solar Atmosphere ◽

Energy Flux ◽

Alfven Waves ◽

Alfvén Waves ◽

Lower Solar Atmosphere

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Injection of Magnetic Energy and Magnetic Helicity into the Solar Atmosphere by an Emerging Magnetic Flux Tube

The Astrophysical Journal ◽

10.1086/367611 ◽

2003 ◽

Vol 586 (1) ◽

pp. 630-649 ◽

Cited By ~ 129

Author(s):

T. Magara ◽

D. W. Longcope

Keyword(s):

Magnetic Flux ◽

Solar Atmosphere ◽

Flux Tube ◽

Magnetic Energy ◽

Magnetic Helicity ◽

Magnetic Flux Tube

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Nonlinear Alfvén wave model of spicules and coronal heating

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308014877 ◽

2007 ◽

Vol 3 (S247) ◽

pp. 195-200

Author(s):

Takahiro Kudoh

Keyword(s):

Wave Model ◽

Alfven Waves ◽

Coronal Heating ◽

Alfven Wave ◽

Magnetic Flux Tube ◽

Alfvén Waves ◽

Theoretical Studies ◽

Mean Square ◽

Cool Loop ◽

Hot Corona

AbstractWe review the theoretical studies of the Alfvén wave model of spicules and coronal heating, mainly based on the papers by Kudoh & Shibata (1999), Saito et al. (2001) and Moriyasu et al. (2004) which performed MHD numerical simulations of nonlinear Alfvén waves propagating along a magnetic flux tube in the solar atmosphere. Kudoh & Shibata (1999) and Saito et al. (2001) found that, if the root mean square of the perturbation is greater than ~ 1 km s−1 in the photosphere, (1) the transition region is lifted up to more than ~ 5000 km (i.e., the spicule is produced), (2) the energy flux sufficient for heating the quiet corona (~ 3.0 × 105 ergs s−1 cm−2) is transported into the corona by Alfvén waves. Moriyasu et al. (2004) demonstrated that a hot corona is created in an initially cool loop as a result of the nonlinear Alfvén waves produced near the photosphere. We conclude that the nonlinear Alfvén wave model is the promising model of spicules and coronal heating.

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