CAPACITANCE OF AN ARRAY OF THICK RODS PARALLEL TO THE GROUND - APPLICATION TO THE ION-CYCLOTRON RESONANCE FREQUENCY ANTENNA OF THE JOINT EUROPEAN TORUS

A variational evaluation of the electrostatic capacitance of an array of thick metal rods parallel to the ground is presented. A straightfor ward procedure allowing unlimited numerical accuracy is given, as well as a simple analytical approximation sufficient for all practical pur poses. The method is applied to the Faraday shield of the JET ICRF ant enna, where it yields a correction of order 40% to the classical thin wire formula.