Cut-off of transverse waves through the solar transition region

Abstract

Context. Transverse oscillations are ubiquitously observed in the solar corona, both in coronal loops and open magnetic flux tubes. Numerical simulations suggest that their dissipation could heat coronal loops, counterbalancing radiative losses. These models rely on a continuous driver at the footpoint of the loops. However, analytical works predict that transverse waves are subject to a cut-off in the transition region. It is thus unclear whether they can reach the corona, and indeed heat coronal loops. Aims. Our aims are to determine how the cut-off of kink waves affects their propagation into the corona, and to characterize the variation of the cut-off frequency with altitude. Methods. Using 3D magnetohydrodynamic simulations, we modelled the propagation of kink waves in a magnetic flux tube, embedded in a realistic atmosphere with thermal conduction, that starts in the chromosphere and extends into the corona. We drove kink waves at four different frequencies, and determined whether they experienced a cut-off. We then calculated the altitude at which the waves were cut-off, and compared it to the prediction of several analytical models. Results. We show that kink waves indeed experience a cut-off in the transition region, and we identified the analytical model that gives the best predictions. In addition, we show that waves with periods shorter than approximately 500 s can still reach the corona by tunnelling through the transition region, with little to no attenuation of their amplitude. This means that such waves can still propagate from the footpoints of loop, and result in heating in the corona.

Accepted for publication in A&A. 8 pages, 7 figures

References in corpus (19)

• PLUTO: a Numerical Code for Computational Astrophysics
• Coronal heating by MHD waves
• Persistent Doppler shift oscillations observed with HINODE/EIS in the solar corona: spectroscopic signatures of Alfvenic waves and recurring upflows
• Nonlinear Instability of kink oscillations due to shear motions
• Fine strand-like structure in the solar corona from MHD transverse oscillations
• First direct measurements of transverse waves in solar polar plumes using SDO/AIA
• A basal contribution from p-modes to the Alfvénic wave flux in the Sun's corona
• Heating by transverse waves in simulated coronal loops
• Excitation of decay-less transverse oscillations of coronal loops by random motions
• The First 3D Coronal Loop Model Heated by MHD Waves against Radiative Losses
• A Fast and Accurate Method to Capture the Solar Corona/Transition Region Enthalpy Exchange
• Wave heating in gravitationally stratified coronal loops in the presence of resistivity and viscosity
• Generating transverse loop oscillations through a steady-flow driver
• The Frequency-dependent Damping of Slow Magnetoacoustic Waves in a Sunspot Umbral Atmosphere
• Wave modes excited by photospheric p-modes and mode conversion in a multi-loop system
• Damping of Propagating Kink Waves in the Solar Corona
• Transverse loop oscillations via vortex shedding: a self oscillating process
• Numerical determination of the cutoff frequency in solar models
• Bayesian evidence for a nonlinear damping model for coronal loop oscillations

Cited by in corpus (6)

• Alfvénic motions arising from asymmetric acoustic wave drivers in solar magnetic structures
• Influence of the Lower Atmosphere on Wave Heating and Evaporation in Solar Coronal Loops
• Decayless oscillations in 3D coronal loops excited by a power-law driver
• Propagating Kink Waves in an Open Coronal Magnetic Flux Tube with Gravitational Stratification: Magnetohydrodynamic Simulation and Forward Modelling
• Kelvin-Helmholtz instability and heating in oscillating loops perturbed by power-law transverse wave drivers
• Spectra of standing kink waves in loops and the effects of the lower solar atmosphere