ANOMALOUS ION HEATING IN VERY-LOW Q(A) DISCHARGES OF THE SINP TOKAMAK

Impurity ion temperatures and their rate of rise were anomalously high (T-i > T-e) in the SINP tokamak having a high current density in a lo w toroidal magnetic field (q(a) approximate to 1.5). The dynamo effect , which is believed to explain the anomaly in such discharges of rever sed-field pinch or ultralow q(a) discharges of other tokamaks cannot a ccount for our heating results. Large fluctuations in n(e), the potent ial and the magnetic field of frequency (omega/2 pi similar to 40-50 k Hz) which appeared during the ion heating indicate large amplitude dri ft-Alfven waves existed in the plasma and caused the anomalous heating by fast stochastic processes. [S0031-9007(98)07363-3].