MEASUREMENTS OF DT ALPHA-PARTICLE LOSS NEAR THE OUTER MIDPLANE OF TFTR

Measurements of DT alpha particle loss to the outer midplane region of TFTR have been made using a radially movable scintillator detector. T he conclusion from this data is that mechanisms determining the DT alp ha loss to the outer midplane are not substantially different from tho se for DD fusion products. Some of these results are compared with a s implified theoretical model for TF ripple induced alpha loss, which is expected to be the dominant classical alpha loss mechanism near the o uter midplane. An example is given of plasma driven MHD induced alpha particle loss to the outer midplane, but no sign of any 'collective' a lpha instability induced alpha particle loss has yet been observed at this location.