Neutron Emission Spectroscopy Results for ITB and Mode Conversion ICRH Experiments at JET
The effect of ICRH on (3He)D plasmas at JET was studied with the TOFOR spectrometer dedicated to 2.5MeV dd neutron measurements. In Internal Transport Barrier (ITB) plasma experiments with large 3He concentrations (X(3He) > 15%) an increase in neutron yield was observed after the ITB disappeared but with the auxiliary NBI and ICRH power still applied. The analysis of the TOFOR data revealed the formation of a high energy (fast) D population in this regime. The results were compared to other mode conversion experiments with similar X(3He) but slightly different heating conditions. In this study we report on the high energy neutron tails originating from the fast D ions and their correlation with X(3He) and discuss the light it can shed on ICRH-plasma power coupling mechanisms.