Radial electric field required to suppress ion temperature gradient modes in the Electric Tokamak

The Electric Tokamak (ET), currently under construction at the University o f California-Los Angeles, is designed to rotate poloidally via a radial cur rent induced by fast wave rf heating fast enough to bifurcate the plasma in to a global "H mode" ("high confinement mode"). A global gyrokinetic code i s used to explore and illustrate some of the effects on ion temperature gra dient turbulence. The realistic radial electric field required to completel y suppress these modes for ET parameters is demonstrated to be <-30 V/cm at its maximum near the half radius. The effects of both a poloidally superso nic bulk rotation threshold and the shear in this rotation near that supers onic threshold were shown to be important in reducing these modes. (C) 1999 American Institute of Physics. [S1070-664X(99)04712-6].