Toward the analysis of waves in the solar atmosphere based on NLTE spectral synthesis from 3D MHD simulations

摘要

From the analysis of Dopplergrams in the K I 7699 A and Na I 5890 A spectrallines observed with the Magneto-Optical filter at Two Heights (MOTH) experimentduring the austral summer in 2002-03 we find upward traveling waves in magneticregions. Our analysis shows that the dispersion relation of these wavesstrongly depends on whether the wave is detected in the low-beta or high-betaregime. Moreover, the observed dispersion relation does not show the expecteddecrease of the acoustic cut-off frequency for the field guided slow magneticwave. Instead, we detected an increase of the travel times below the acousticcut-off frequency and at the same time a decrease of the travel time above it.To study the formation height of the spectral lines employed by MOTH in greaterdetail we are currently in the process of employing 3D MHD simulations carriedout with CO5BOLD to perform NLTE spectral synthesis.