Helical reconnections of the reversed field pinch

A model of helical reconnection of magnetic surfaces, originally proposed as a mechanism for Tokamak internal disruptions, is applied to more general diffuse pinch configurations, particularly the Reversed Field Pinch. A number of new phenomena are predicted. Notably it is shown that inverse reconnections, proceeding in a direction opposite to that previously considered, are expected. These can give rise to self-reversal of the toroidal field leading to axisymmetric reversed field states, either by a complete reconnection of the magnetic axis or by an incomplete reconnection of limited radial extent, not reconnecting the inner surfaces.