RELAXED AND PARTIALLY RELAXED MAGNETIC EQUILIBRIA IN TIGHT-ASPECT-RATIO TORI

Force-free equilibrium magnetic fields in tight-aspect-ratio toroidal configurations are investigated. The study is mainly directed to model ling field configurations in the 'rodomak', a modification to the SPHE X gun-injected spheromak in which a current-carrying rod is inserted a long the geometric axis. A family of analytical relaxed states (del x B = muB, mu constant) is presented for a torus of rectangular cross se ction, with boundary conditions allowing for flux embedded in the wall s, representing the gun. Numerically calculated fields in SPHEX geomet ry, with mu profiles relevant to the driven phase of operation, are al so given. The dependence of the field configurations and global quanti ties such as energy, helicity and toroidal current on the controlling parameters (gun flux, gun current and rod current) and geometry is dis cussed.