ICRF heating scenarios in JET with emphasis on He-4 plasmas for the non-activated phase of ITER

In the initial phase of ITER operation, He-4 plasmas could be used in order to avoid activating the machine. The main ICRH scenarios foreseen for ITER He-4 plasmas are (He-3)He-4 and (H)He-4. ICRH experiments have been carried out on JET using He-4 plasmas to validate these scenarios. At the same time, conditions for access to H-mode in plasmas of various isotope compositions from dominantly He-4 to dominantly D have been studied. Experiments have also been carried out for the first time in He-4 plasmas with the ICRF power added to He-4 neutral beam injection at the third harmonic of He-4 in order to produce a He-4 tail for alpha particle studies. (Author)