Observations of neutral beam and ICRF tail ion losses due to Alfven modes in TFTR

Fast ion losses resulting from MHD modes at the Alfven frequency, such as the TAE, have been observed in TFTR. The modes have been driven both by neutral beam ions, at low BT, and by H-minority ICRF tail ions at higher BT. The measurements indicate that the loss rate varies linearly with the mode amplitude, and that the fast ion losses during the mode activity can be significant, e.g. up to 10% of the input power is lost in the worst case