A combined technique for the global optimization of the inverse electromagnetic problem solution

A method for finding the global optimum of the electromagnetic inverse problem solution is presented. The problem consists in the determination of the current system which produces a given magnetic field within a domain of finite extent. An infinite class of solutions exists. In order to find the solution of the synthesis problem obtained, a global optimization technique, based on the combination of the filled function (FF) method and the evolution strategy (ES) method, is developed. The FF method is utilized to find a sequence of regions containing decreasing minima. The minimization inside this region is done by means of the ES method. The technique described has been utilized for the poloidal magnetic system of a toroidal device for thermonuclear fusion experiments and for the main coil system of a nuclear magnetic resonance (NMR) device.