Effects of sheared rotation on ion-temperature-gradient-driven instabilities

Effects of the sheared toroidal rotation on the ion-temperature-gradient-driven (ITG) modes are studied. The kinetic integral solution is derived for the ITG modes in the toroidally rotating plasma and is numerically solved to obtain the growth rate, the real frequency, and the mode eigenfunction. In the presence of the toroidal flow shear, the radial wavenumber in the ballooning representation depends on the time. Accordingly, the growth rate and the real frequency are also interpreted as functions of time. The mode eigenfunction moves poloidally and is stabilized in the good curvature region. In this way, the toroidal flow shear is expected to cause a significant reduction of the average growth rate.