Axisymmetric reversed-field pinch configuration with global invariants

An axisymmetric reversed-field pinch (RFP) configuration is analyzed by minimizing a potential energy of a plasma, subject to the Woltjer's invariant K and the invariants of both a longitudinal flux Φ and a poloidal flux χ, as well as a reasonable boundary condition of J = 0 on the wall. An equilibrium equation, J x B = grad p is also taken as the local constraint. The obtained RFP configuration has the high beta value of 17.7 % on the axis and satisfies the Suydam's criterion as well as the ideal MHD and tearing mode stability criterion for the m = 1 mode. In this RFP, the field reversal ratio F and pinch ratio θ are about -1.2 and 2.48 respectively. The components of the magnetic fields, Bθ and Bz are also given in analytical expressions. (author)