Patent Number: 051475960
Section: abstract

A method and apparatus for plasma relaxation under magnetic global topological constraint produces a hot magnetically confined toroidal Z-pinch plasma with a plurality of straight and toroidal relaxing plasma discharges so as to generate at least one open-ended poloidal null separatrix in the magnetic field with one poloidal null within the plasma space situated in the small major radius side of the toroidal discharge, forming thereby a magnetic configuration (called DAG) with non-zero homotopic invariant, including a toroidal reversed-field pinch with inner poloidal divertor, in a region of open plasma magnetic surfaces surrounding the toroidal discharges, when toroidal magnetic field component is also made to be substantially different from zero at the poloidal null. The topologically constrained relaxation invention, called topomak, may be operated in equilibria with regions of nested closed magnetic surfaces of high magnetic shear with safety factor Q radially varying from negative, but greater than -1, values to +infinity, and with high plasma/magnetic pressures ratio, closed to known theoretical stability conditions, the topological invariant opposing plasma relaxation to less favorable lower-energy states without reversal. The toroidally reversed poloidal divertor is effectively produced in the topomak by replacing the solid conducting inner core of prior art reversed-field-pinch relaxation devices by straight-pinch-like current discharge of plasma along the major axis under conditions where the topological constraint holds. The DAG plasma configuration has cylindrical topology.