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.