It is shown by considering the general properties of solution of the kineti
c equation that plasma rotation in radio-frequency (RF) wave-heated tokamak
plasmas can be modeled by the RF-modified plasma viscous force. This appro
ach is qualitatively different from a model that uses a radial current to m
odel the RF effects on plasma rotation. (C) 2000 Elsevier Science B.V. All
rights reserved.