Proceedings of the School and Workshop on Space Plasma Physics vol:1121 pages:99-105
Proceedings of the School and Workshop on Space Plasma Physics location:Sozopol, Bulgaria date:31 August - 7 September 2008
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. Both foot point shearing and magnetic flux emergence are used as a triggering mechanism in this model. The 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 two triggering mechanisms and find that the overall evolution of the systems are similar.