CRISIS-INDUCED INTERMITTENCY IN TRUNCATED MEAN-FIELD DYNAMOS

We investigate the detailed dynamics of a truncated alpha omega dynamo model with a dynamic alpha effect. We find the presence of multiple a ttractors, including two chaotic attractors with a fractal basin bound ary that merge to form a single attractor as the control parameter is increased. By considering phase portraits and the scaling of averaged times of transitions between the two attractors, we demonstrate that t his merging is accompanied by a crisis-induced intermittency. We also find a range of parameter values over which the system has a fractal p arameter dependence for fixed initial conditions. To the authors' know ledge, this is the first time this type of intermittency has been obse rved in a dynamo model and it could be of potential importance in acco unting for some forms of intermittency in the solar and stellar output .