Nonlinear propagation of Alfven waves driven by observed photospheric motions: Application to the coronal heating and spicule formation

TL;DR

This study uses MHD simulations driven by observed photospheric motions to demonstrate how Alfven wave resonance can enhance energy transfer, potentially explaining coronal heating and spicule formation.

Contribution

It introduces a model showing Alfven wave resonance driven by observed photospheric spectra, highlighting its role in coronal heating and spicule dynamics.

Findings

Resonant frequencies at 1, 3, and 5 mHz identified.

Observed spectrum leads to higher energy flux and transition region height.

Alfven wave resonance enhances energy transfer to the corona.

Abstract

We have performed MHD simulations of Alfven wave propagation along an open flux tube in the solar atmosphere. In our numerical model, Alfven waves are generated by the photospheric granular motion. As the wave generator, we used a derived temporal spectrum of the photospheric granular motion from G-band movies of Hinode/SOT. It is shown that the total energy flux at the corona becomes larger and the transition region height becomes higher in the case when we use the observed spectrum rather than white/pink noise spectrum as the wave generator. This difference can be explained by the Alfven wave resonance between the photosphere and the transition region. After performing Fourier analysis on our numerical results, we have found that the region between the photosphere and the transition region becomes an Alfven wave resonant cavity. We have confirmed that there are at least three resonant frequencies, 1, 3 and 5 mHz, in our numerical model. Alfven wave resonance is one of the most effective mechanisms to explain the dynamics of the spicules and the sufficient energy flux to heat the corona.