Design of the IGNITOR ICRF system

A complete antenna and feeding system has been designed for the Ion Cyclotron Resonance Frequency (ICRF) system of the IGNITOR experiment, planned to operate in the 90 140 MHz frequency range. The design of the antenna is based on the conventional strap antenna element and on a single layer Faraday shield, and in our proposed design each strap is fed by a RF power generator via a coaxial cable and a tuning and matching system. The coupling properties of the antenna are calculated with a slab model of the plasma. For the electrical part of the design an innovative tool has been used. The Virtual Prototyping Laboratory permits to analyze the antenna in a realistic geometry and to accurately calculate the antenna parameters. Resulting from this analysis, each antenna is able to withstand 4 MW of RF power. A detailed design has been carried out to prevent arching in the vacuum vessel and to reduce the connection lengths. A complete thermal and mechanical analysis of the antenna has been completed and engineering solutions are reported. Detailed mechanical drawings of the IGNITOR antenna are presented