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We study the conversion of fast magneto-acoustic waves to Alfven waves by means of 2.5D numerical simulations in a sunspot-like magnetic configuration. A fast, essentially acoustic, wave of a given frequency and wave number is generated…

Solar and Stellar Astrophysics · Physics 2015-06-03 Elena Khomenko , Paul Cally

The conversion of fast waves to the Alfven mode in a realistic sunspot atmosphere is studied through three-dimensional numerical simulations. An upward propagating fast acoustic wave is excited in the high-beta region of the model. The new…

Solar and Stellar Astrophysics · Physics 2015-06-11 T. Felipe

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,…

Astrophysics · Physics 2009-11-13 P. S. Cally , M. Goossens

In this paper, results of 2.5-dimensional magnetohydrodynamical simulations are reported for the magnetic reconnection of non-perfectly antiparallel magnetic fields. The magnetic field has a component perpendicular to the computational…

Solar and Stellar Astrophysics · Physics 2015-05-18 Hiromitsu Kigure , Kunio Takahashi , Kazunari Shibata , Takaaki Yokoyama , Satoshi Nozawa

Alfv\'en waves may be generated via mode conversion from fast magneto-acoustic waves near their reflection level in the solar atmosphere, with implications both for coronal oscillations and for active region helio-seismology. In active…

Solar and Stellar Astrophysics · Physics 2015-05-28 Paul S. Cally , Shelley C. Hansen

Coupling between fast magneto-acoustic and Alfv\'en waves can be observe in fully ionized plasmas mediated by stratification and 3D geometrical effects. In Paper I, Cally & Khomenko (2015) have shown that in a weakly ionized plasma, such as…

Solar and Stellar Astrophysics · Physics 2019-01-16 P. A. González-Morales , E. Khomenko , P. S. Cally

A new method for the determination of the Alfven wave energy generated during magnetic reconnection is introduced and used to analyze the results from two-dimensional MHD simulations. It is found that the regions with strong Alfven wave…

Plasma Physics · Physics 2015-06-11 L. C. Wang , L. J. Li , Z. W. Ma , X. Zhang , L. C. Lee

Aims: Propagation and energy transfer of torsional Alfv\'en waves in solar magnetic flux tubes of axial symmetry is studied. Methods: An analytical model of a solar magnetic flux tube of axial symmetry is developed by specifying a magnetic…

Solar and Stellar Astrophysics · Physics 2015-05-20 K. Murawski , A. Solov'ev , Z. E. Musielak , A. K. Srivastava , J. Kraskiewicz

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…

Solar and Stellar Astrophysics · Physics 2021-08-06 Abbas Raboonik , Paul Cally

Complete asymptotic expansions are developed for slow, Alfv\'en and fast magnetohydrodynamic waves at the base of an isothermal three-dimensional (3D) plane stratified atmosphere. Together with existing convergent Frobenius series solutions…

Solar and Stellar Astrophysics · Physics 2021-12-28 Paul S. Cally

We use the exact solutions for magnetoacoustic waves in a two dimensional isothermal atmosphere with uniform inclined magnetic field to calculate the wave reflection, transmission, and conversion of slow and fast waves incident from above…

Solar and Stellar Astrophysics · Physics 2016-01-27 Shelley Hansen , Paul Cally , Alina Donea

We show that 5-minute acoustic oscillations may resonantly convert into Alfv{\'e}n waves in the $\beta{\sim}1$ region of the solar atmosphere. Considering the 5-minute oscillations as pumping standing acoustic waves oscillating along…

Astrophysics · Physics 2007-05-23 D. Kuridze , T. V. Zaqarashvili , B. Roberts

Here we investigate the contribution of surface Alfven wave damping to the heating of the solar wind in minima conditions. These waves are present in regions of strong inhomogeneities in density or magnetic field (e. g., the border between…

Solar and Stellar Astrophysics · Physics 2015-05-14 R. M. Evans , M. Opher , V. Jatenco-Pereira , T. I. Gombosi

Rapid shear motion of magnetar crust can launch Alfv\'{e}n waves into the magnetosphere. The dissipation of the Alfv\'{e}n waves has been theorized to power the X-ray bursts characteristic of magnetars. However, the process by which…

High Energy Astrophysical Phenomena · Physics 2025-06-10 Dominic Bernardi , Yajie Yuan , Alexander Y. Chen

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…

Solar and Stellar Astrophysics · Physics 2015-06-23 Carlos Rijs , Hamed Moradi , Damien Przybylski , Paul S. Cally

The detection of upward propagating internal gravity waves at the base of the Sun's chromosphere has recently been reported by Straus et al., who postulated that these may efficiently couple to Alfven waves in magnetic regions. This may be…

Solar and Stellar Astrophysics · Physics 2015-05-14 Marie Newington , Paul Cally

Magnetic fields are key ingredients for heating the solar corona to temperatures of several million Kelvin. A particularly important region with respect to this is the so-called magnetic canopy below the corona, where sound and Alfv\'en…

Solar and Stellar Astrophysics · Physics 2023-01-23 Th. Gundrum , J. Forbriger , Th. Herrmannsdörfer , G. Mamatsashvili , S. Schnauck , F. Stefani , J. Wosnitza

We have performed a 2.5 dimensional magnetohydrodynamic simulation that resolves the propagation and dissipation of Alfven waves in the solar atmosphere. Alfvenic fluctuations are introduced on the bottom boundary of the extremely large…

Solar and Stellar Astrophysics · Physics 2015-06-18 Takuma Matsumoto , Takeru K. Suzuki

We present two-dimensional simulations of wave propagation in a realistic, non-stationary model of the solar atmosphere. This model shows a granular velocity field and magnetic flux concentrations in the intergranular lanes similar to…

Solar and Stellar Astrophysics · Physics 2010-09-29 C. Nutto , O. Steiner , M. Roth

Observations of the solar atmosphere show that internal gravity waves are generated by overshooting convection, but are suppressed at locations of magnetic flux, which is thought to be the result of mode conversion into magneto-acoustic…

Solar and Stellar Astrophysics · Physics 2017-02-01 G. Vigeesh , J. Jackiewicz , O. Steiner
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