  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.
