Faraday shield effects on a half-turn loop antenna used for ICRF plasma heating

The characteristics of a half-turn loop antenna having a Faraday shield (used for ion-cyclotron RF plasma heating) have been systematically investigated. The main interest is to clarify the Faraday shield effects on the near-zone electric field distribution. It has been confirmed that, in the presence of the Faraday shield, undesirable field components are sufficiently suppressed, and the heating component E/sub y/, which otherwise is strongly localized as an end effect, has been found to be distributed uniformly along the antenna in the case of a short electric length. It is found that the shielding strips should be uniformly distributed over the entire region around the half-turn loop antenna.>