INFLUENCE OF RADIAL ELECTRIC-FIELD ON ALFVEN-TYPE INSTABILITIES

The influence of the large-scale radial electric field, E(r)(0) on the frequency of shear-Alfven-type instability is analyzed. A frozen-in-f lux constraint and the moderate-beta ion gyrokinetic equation are used in the derivation. The present analysis indicates that the frequency predicted by a theory without E(r)(0) effect should be Doppler shifted by k.V(E) for comparison to the experimentally observed frequency. A specific example of the practical relevance of the result is given reg arding possible identification of the edge-localized-mode-associated m agnetic activity recently observed in PBX-M [Plasma Physics and Contro lled Nuclear Fusion Research (International Atomic Energy Agency, Vien na, 1989), Vol. 1, p. 97] tokamak experiment.