INDICATORS OF RECONNECTION PROCESSES AND TRANSITION TO GLOBAL CHAOS IN NONTWIST MAPS

Reconnection processes of twin-chains are systematically studied in th e quadratic twist map. By using the reversibility and symmetry of the mapping, the location of the indicator points is theoretically determi ned in the phase space. The indicator points enable us to obtain usefu l information about the reconnection processes and the transition to g lobal chaos. We succeed in deriving the general conditions for the rec onnection thresholds. In addition, a new type of reconnection process which generates shearless curves is studied.