A model of field reversal in the diffuse pinch

It is shown that random reconnections of magnetic field lines in a diffuse pinch can lead to the appearance of reversed axial field near the discharge tube wall. It is suggested that the magnitude of the effect will depend on the degree to which current can be exchanged between adjacent field lines at a point of reconnection and on this basis a mathematical model is developed which describes magnetic field configurations of the diffuse pinch which are intermediate between two extremes: the force-free paramagnetic model with no field reversal in the limit where the current does not follow the field at all at a recombination point, and the Bessel function model in the limit where the current rigorously follows the field lines. An iterative procedure for the generation of intermediate configurations is described, and numerical results are presented and compared with experimental results from ZETA.