Talk abstract details

Classical tools of helioseismology usually rely on waves with frequencies below the acoustic cut-off frequency and which are trapped inside the acoustic cavity of the Sun. High frequency waves above the acoustic cut-off frequency, however, travel freely into the solar atmosphere. On their path through the atmosphere, these waves interact with the magnetic field. This interaction includes mode conversion, transmission, and refraction. Observations of these waves at different heights can be used to probe the magnetically structured atmosphere as for example present in active regions. However, the tools to explore these magneto-acoustic waves at different heights are still very basic.

We use numerical simulations of the propagation of high frequency magneto-acousitc waves in a realistic solar atmosphere including granular velocity fields. We present two-dimensional and three-dimensional simulations carried out with the CO5BOLD code. In the simulations we use waves that are excited by acoustic events immediately below the photosphere. The results demonstrate that mode conversion occurs and that the waves are partially refracted back into the solar atmosphere and are partially transmitted into the chromosphere. Furthermore, these simulations can now be used to test present analysis tools and develop new techniques for the interpretation of observations of high frequency waves. We are interested in deriving new observational quantities for the helioseismic exploration of the chromosphere.