Anomalous and neoclassical transport suppression by the radial electric field, induced by Alfven waves in tokamaks

The suppression of anomalous transport and/or reduction of neoclassical tra nsport caused by the Alfven-wave-induced shear of the radial electric field in tokamaks is investigated. The simple quantitative estimates reported in previous papers are checked by a consistent evaluation of the profile of t he radial electric field created by the resonant absorption of Alfven waves . The radial variations of the ion viscosity and heat conductivity across t he mode conversion layer are evaluated both in the banana and potato region s. In agreement with previous analytical results, it is shown that the kine tic Alfven waves may play the role of a convenient mechanism for reduction of anomalous and neoclassical transport and formation of transport barriers in tokamaks. (C) 1999 American Institute of Physics. [S1070-664X(99)02609- 9].