Evaluation of optimum operational frequency range for inductively coupled radio - frequency ion source: study of the ELISE source case

Neutral beam injection for plasma heating and current drive is necessary in ITER tokamak. Due to its various advantages, a RF driven plasma source type was selected as a reference ion sourc e for the ITER H NBI. The operational working frequency for these inductively coupled ion sources has chosen to be 1 MHz. In the frame of the work - program for the FUSION - DC PhD thesis: " Studies and experimental activities to qualify the behaviour of RF po wer circuits for Negative Ion Sources of Neutral Beam Injectors for ITER and fusion experiments " and of the activities launched during the first mobility period at the Host Institution: IPP, t his document provides a study and methodology to find the optimu m operational frequency range for the inductively coupled RF ion sources. Furthermore, based on the codes developed, the verification of the operational working frequency of 1 MHz is analyzed for the case of the RF ion source ELISE (present at IPP, Garchin g, Germany), a half size ITER NBI source.