A method and apparatus is described comprising of a plurality of electromagnetic resonant structures coupled to a common process or reaction volume, such that resonance of each structure is maintained while the process or reaction volume is a part of each resonant structure. At the same time, each resonant structure is matched to its respective electromagnetic generator. Such a system allows each generator and its delivery system to run at rated power, with summation of all the powers occurring in the common process or reaction volume. In various embodiments of this invention, the various electromagnetic generators can run at the same or different frequencies. The various resonant structures can be single mode or multimode, or a mixture of single mode and multi mode. The various resonant structures can be arranged spatially in order to couple several structures to the process or reaction volume. Various spatial arrangements also allow coupling of either the electric or the magnetic field to the process or reaction volume, as well as allowing the generation of rotating fields in the process or reaction volume with any orientation of the rotating field with respect to the process or reaction volume.