Abstract

WANDURRAGA, Paula C.; NAVARRO, Anamaria  and  LORA-CLAVIJO, Fabio D.. Torsional Alfvén Waves Propagation in a Stratified Solar Atmosphere. Rev. acad. colomb. cienc. exact. fis. nat. [online]. 2021, vol.45, n.174, pp.52-66.  Epub Sep 12, 2021. ISSN 0370-3908.  https://doi.org/10.18257/raccefyn.1245.

Observations indicate that the magnetic field in the solar atmosphere is twisted, playing an important role in different solar phenomena, such as magnetic reconnection or solar flaring activity, among others. However its influence on these kind of phenomena remains unclear. Motivated by this, we study, through several 3D numerical simulations, the effect of the magnetic field twist on the propagation of torsional Alfvén and magneto-acoustic waves moving along the photosphere and the lower chromosphere in the quiet Sun. In order to simulate the dynamics of these magnetohydrodynamic (MHD) waves, we solve numerically the ideal 3D linearized MHD equations by assuming a quiet Sun, which is excited by an initial twist perturbation in the velocity vector field, for six different values of the twist parameter and three equilibrium magnetic field strengths. Particularly, we analyze the 3D morphology of the velocity and magnetic fields lines, and the spatial profiles of the transversal component of these fields associated with the torsional Alfvén waves. The results of our numerical simulations reveal the magnetic field amplification due to the twist parameter. Specifically, we have observed that this quantity increases as the twist parameter increases and decreases for larger values of the equilibrium magnetic strength. Moreover, we show that the maximum of amplification as function of the twist has an exponential behavior. Finally, we notice that the Poynting vector flux is greater for larger values of the initial twist but is smaller for more intense equilibrium magnetic fields.

Keywords : MHD; Solar Atmosphere; Numerical Methods.

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