Reconnection of twisted flux tubes as a function of contact angle

The collision and reconnection of magnetic flux tubes in the solar corona has been proposed as a mechanism for solar flares and in some cases as a model for coronal mass ejections. We study this process by simulating the collision of pairs of twisted flux tubes with a massively parallel, collocation, viscoresistive, magnetohydrodynamic code using up to 256 x 256 x 256 Fourier modes. Our aim is to investigate the energy release and possible global topological changes that can occur in flux-tube reconnection. We have performed a number of simulations for different angles between the colliding flux tubes and for either co- or counterhelicity flux tubes. We find the following four classes of interaction : (1) bounce (no appreciable reconnection), (2) merge, (3) slingshot (the most efficient reconnection), and (4) tunnel (a double reconnection). We will describe these four classes of flux-tube reconnection and discuss in what range of parameter space each class occurs and the implications our results have for models of flares and coronal mass ejections.