---------------------------------------- Type of abstract: Contributed Presenter Name: I. S. Veselovsky Status of first author: non-student ---------------------------------------- Title: Magneto-acoustico-gravity (MAG) waves generated by explosive events in the solar atmosphere ---------------------------------------- Authors: I.S. Veselovsky Institute of Nuclear Physics Moscow State University 119899 Moscow Russia E-mail: veselov@dec1.sinp.msu.ru ---------------------------------------- Abstract: The propagation of the perturbations in the solar chromosphere (Moreton waves or flare blast waves) and in the corona (coronal shock waves or EIT waves) after impulsive solar flares is considered. The interpretation is discussed that Moreton waves are associated with vertical motions traveling horizontally mainly as a gravity mode with a moderate compression in the chromosphere. Such an interpretation is supported by the observations in the H-alpha line wings. The round shaped fronts of the large-scale coronal shock waves are puzzling when taking into account only the large-scale structures of the magnetic fields and plasma in the corona. The tentative explanation could be found in the existence of the much stronger pressure balanced small-scale loops with low and high beta plasma parameters in the unperturbed solar corona. In this case, the nonlinear MAG wave decays and splits into linear modes traveling independently with their characteristic speeds through the "preferred channels" in the inhomogeneous medium. Slow magnetosonic or sound pulses tend to occur in the pressure balanced regions with highest beta values. They are found in observations as brightening rims averaged over many small-scale loops. Simple analytical models of these phenomena are presented and possible space weather applications are indicated. ---------------------------------------- International Solar Cycle Studies (ISCS/SCOSTEP) Solar Atmosphere Solar Corona and Heliosphere Space Weather (part of S-RAMP/SCOSTEP)