Electric Field Amplification inside a Porous Spherical Cavity Resonator Excited by an External Plane Wave

Abstract

A spherical polyhedron constructed from open surface polygons is an electromagnetic wave resonator that can be excited by an external plane wave. The resonant frequencies of the porous sphere depend on the radius of the sphere and the area of the openings in the surface of the sphere. The strength of the internal electric fields varies with the width of the conducting edges that comprise the polyhedron frame. At the optimum edge width, the external EM wave field excites the strongest internal field amplitudes. The WIPL-D EM simulation model is used to determine the optimum porous resonator for polyhedrons with 180 and 960 vertices. All of the cavity modes for a solid spherical cavity resonator can be excited in the porous spherical cavity resonator (PSCR). With a high resonator Q, an EM plane-wave of 1 V/m can excite an internal electric field of over 1000 V/m that takes finite time for fields to build up. The spherical cavity modes provide a variety of electric field distributions at the interior of the PSCR. The PSCR may be used to greatly increase the electric fields of a high power radio beam in order to produce isolated plasma clouds by neutral gas breakdown.