Torsional wave dispersion and dissipation in solar tornados

¹ Faculty of Physics, University of Tabriz, Tabriz, Iran
² Department of Physics, Tafresh University, Tafresh 39518 79611, Iran

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Received: 19 February 2026
Accepted: 12 April 2026

Abstract

Aims. We investigated the nature of solar atmosphere tornados hosting torsional Alfvén waves and fast magnetoacoustic torsional waves in the context of energy transport and transfer.

Methods. Solar tornados created by equilibrium magnetic twist and plasma rotation were modeled and studied analytically by implementing the resistive magnetohydrodynamic theory in cylindrical geometry. The dispersion relations were obtained by the second-order thin flux-tube approximation in the linear regime to enable us to consider damping effects connected with magnetic diffusivity and plasma viscosity.

Results. The obtained implicit dispersion relation provides a broad picture of the significance of the equilibrium and atmosphere conditions in addition to dissipative effects. The damping depends on the magnetic twist and plasma rotation in addition to the plasma-β effects. The efficiency of damping due to magnetic diffusivity is enhanced by stronger equilibrium-twisted magnetic fields. The torsional fast magnetoacoustic wave is more affected by dispersion in the limit of zero plasma β in the presence of diffusive and viscous effects. The dispersion due to magnetic diffusivity is enhanced by the plasma β. The plasma viscosity enhances the efficiency of the plasma β regarding dispersion effects. The damping of torsional fast magnetoacoustic waves in solar tornados due to magnetic diffusivity is proportional to the equilibrium magnetic twist for photospheric and coronal conditions. The efficiency of damping is higher in photospheric conditions. The viscosity has a stronger damping effect in lower plasma-β conditions. In photospheric conditions, the equilibrium magnetic twist has a stronger damping effect than in coronal conditions, when magnetic diffusivity and plasma viscosity are both present.

Conclusions. The model provides a theoretical basis for development of magnetohydrodynamic seismology of solar tornados. The combined dissipative effects we illustrate clearly show that the damping due to magnetic diffusivity is significantly enhanced in the presence of plasma viscosity. As damping is a feature of resistance, various modes dissipate subject to atmosphere conditions. This provides a sustainable heating mechanism in the solar atmosphere.