J. Pomoell, R. Vainio
Department of Physical Sciences, University of Helsinki, Finland
We study the MHD processes related to a piston-like flare/CME event in the lower solar corona using numerical simulations. Our intial state is an over-pressured unequilibrium flux rope with initial velocity away from the Sun. The results show that as the flux rope rises, a shock structure is formed, reaching from ahead of the flux rope all the way to the solar surface. Even if the flux rope quickly decelerates and is unable to escape from the system, the shocks continue to propagate, one front moving away from the Sun and another sweeping the solar surface. The relation to observed radio signatures and wave phenomena on the solar disk are discussed.