COMPARISON OF EXACT AND APPROXIMATE SOLUTIONS OF THE SCHUMANN RESONANCE PROBLEM FOR THE KNEE CONDUCTIVITY PROFILE

Abstract

The rapid development of computer technology allows for the direct numerical solution of the electromagnetic resonance problem in the Earth–ionosphere cavity. Either the two-dimensional telegraph equations (2DTU) or the finite element method in the time domain (FDTD) techniques are used. The direct solutions apply the same models of the conductivity profile of atmosphere as those applied in ordinary solutions. However, it is forgotten that these profiles are nothing else, but a convenient interpretation for the approximate heuristic relations for deriving the propgation constant. Since the full wave solution of the electromagnetic problem for such a profile does not coincide with the aproximate one, the direct numerical solutions must also deviate from the heuristic one. We apply the knee conductivity profile in the rigorous full wave solution and in the approximate solution and evaluate their devations

Keywords

• global electromagnetic resonance
• rigorous and approximate solutions
• the knee profile