An experiment was performed on the TEXTOR tokamak which proves that the plasma can be heated by ion cyclotron resonance using antennas without a Faraday shield. The heating performance of the unshielded antenna was found to be similar to that of a shielded antenna. Although the radiated power was somewhat higher with the unshielded antenna, no impurity problems were encountered. These results are explained on the basis of radiofrequency sheath theory and by the almost perfect shielding of parallel electric fields by the plasma. Implementation criteria for unshielded antennas were obtained.
Multipactor predictions for ion cyclotron resonance heating antennas of the tokamak WEST