Poster abstract

We study the initiation and early evolution of coronal mass ejections (CMEs) in the framework of numerical ideal magnetohydrodynamics (MHD). The magnetic field of the active region possesses a topology in order for the breakout model to work. An initial multi-flux system in steady equilibrium containing a pre-eruptive region consisting of three arcades with alternating flux polarity is kept in place by the magnetic tension of the overlying closed magnetic field of the helmet streamer. The effects of two different driving mechanisms (shearing motions along the magnetic inversion line and emergence of new magnetic flux) are separately studied and then compared. The applied boundary conditions cause the central arcade to expand and lead to the eventual ejection of the top of the helmet streamer. We compare the topological and dynamical evolution of the obtained CMEs and find that the overall evolution of the systems is similar.