Analysis of self-organization phenomena of a toroidally-diverted reversed field pinch plasma

Reversed field pinch plasma has been found to show some new aspects from the view-point of self-organization phenomena, when the toroidal divertor fields are externally applied. Although this toroidally asymmetric plasma is similar to the divertor-less plasma in terms of attractors, it has a response to the externally applied divertor fields, i.e., the field reversal inside the separatrix is deeper than that of the superposition of the vacuum divertor field and the divertor-less plasma magnetic field. In addition, this configuration is sustained by intermittent and pulsive m=0 modes, instead of the m=1 kink modes which are usually observed in the dynamo of the divertor-less reversed field pinch. These phenomena are compared with analysis of configuration and stability by using a higher order force-free Bessel function model. (author)