Experimental and theoretical studies of ion cyclotron heating on Jet

Minority ICRF experiments are described which exploit the special features of highly localised heating and fast ion production. Power modulation during sawtooth stabilised periods has provided power deposition profiles, direct electron heating fractions and electron thermal diffusion coefficients inside the q = 1 surface. He3-D fusion reaction experiments with energetic He3 minority ions have produced 60kW of fusion power. These results agree well with both a Stix model and a combined global wave/Fokker Planck model. On-axis ICRH during the current rise of high current discharges has achieved central electron temperatures and D-D reaction rates up to twice as high as those obtained with heating in the current flat top. The first JET H-modes with substantial combined RF and neutral beam injection heating have been produced in a double null X-point configuration