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

摘要

We have performed MHD simulations of Alfven wave propagation along an openflux tube in the solar atmosphere. In our numerical model, Alfven waves aregenerated by the photospheric granular motion. As the wave generator, we used aderived temporal spectrum of the photospheric granular motion from G-bandmovies of Hinode/SOT. It is shown that the total energy flux at the coronabecomes larger and the transition region height becomes higher in the case whenwe use the observed spectrum rather than white/pink noise spectrum as the wavegenerator. This difference can be explained by the Alfven wave resonancebetween the photosphere and the transition region. After performing Fourieranalysis on our numerical results, we have found that the region between thephotosphere and the transition region becomes an Alfven wave resonant cavity.We have confirmed that there are at least three resonant frequencies, 1, 3 and5 mHz, in our numerical model. Alfven wave resonance is one of the mosteffective mechanisms to explain the dynamics of the spicules and the sufficientenergy flux to heat the corona.