Application of Epstein technique to study the coupling properties of an ICRH antenna

An analytic solution of the wave equation for an inhomogeneous Tokamak plasma is obtained in terms of hypergeometric functions by fitting the Epstein profile, with a maximum of five free parameters, to the dispersion curve. Power radiated from an ICRH antenna is then evaluated by solving a boundary value problem. The radiation resistance and inductance obtained by this method are compared in a particular case, for illustration, with those employing numerical integration and are found to be typically 10% higher. Replacing the numerical integration by the curve fitting procedure in the plasma region, a considerable saving of computer time can be achieved.