Fast particles and the edge transport barrier

The role of fast particles in the edge transport barrier formation is discussed. Analysis of recent experiments on JET which has been carried out in H, D, T and DT mixture with NBI and ICRH heating is presented which supports the idea that the width of the edge transport barrier is controlled by the banana width of the fast beam ions in case of NBI heating and by the banana width of the thermal ions in case of ICRH minority heating. A simple theoretical model which can account for this effect is analysed. (author)