C. Francile

Hα Moreton waves observed on December 06, 2006 - A 2D case study

Fil: Francile, Carlos Natale. Universidad Nacional de San Juan. Facultad de Cs.exactas Fisicas y Naturales. Departamento de Informatica. Observat.astron. Felix Aguilar;

Moreton and EUV Waves Associated with an X1.0 Flare and CME Ejection

A Moreton wave was detected in active region (AR) 12017 on 29 March 2014 with very high cadence with the H-Alpha Solar Telescope for Argentina (HASTA) in association with an X1.0 flare (SOL2014-03-29T17:48). Several other phenomena took place in connection with this event, such as low-coronal waves and a coronal mass ejection (CME). We analyze the association between the Moreton wave and the EUV signatures observed with the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory. These include their low-coronal surface-imprint, and the signatures of the full wave and shock dome propagating outward in the corona. We also study their relation to the white-light CME. We perform a kinematic analysis by tracking the wavefronts in several directions. This analysis reveals a high-directional dependence of accelerations and speeds determined from data at various wavelengths. We speculate that a region of open magnetic field lines northward of our defined radiant point sets favorable conditions for the propagation of a coronal magnetohydrodynamic shock in this direction. The hypothesis that the Moreton wavefront is produced by a coronal shock-wave that pushes the chromosphere downward is supported by the high compression ratio in that region. Furthermore, we propose a 3D geometrical model to explain the observed wavefronts as the chromospheric and low-coronal traces of an expanding and outward-traveling bubble intersecting the Sun. The results of the model are in agreement with the coronal shock-wave being generated by a 3D piston that expands at the speed of the associated rising filament. The piston is attributed to the fast ejection of the filament–CME ensemble, which is also consistent with the good match between the speed profiles of the low-coronal and white-light shock waves.