Radial electric field shear generation by drift-thermal turbulence

The self-consistent radial electric field shear generated by a drift-thermal turbulence is:studied in some detail. A set of new dynamical equations is derived. In this model, there exist three kinds of equilibrium states. The first is the zero shear state of the radial electric field; the second is the positive shear state of the radial electric field; and the third is the negative shear state of the radial electric field. But only the negative shear state may be stable. Two kinds of stable states with the negative shear radial electric field are relevant td: the behavior such as that exhibited by high (H) mode and by edge localized modes (ELMs), respectively. (C) 1997 American Institute of Physics.