RADIAL ELECTRIC-FIELD SHEAR GENERATION BY DRIFT-THERMAL TURBULENCE

The self-consistent radial electric field shear generated by a drift-t hermal turbulence is:studied in some detail. A set of new dynamical eq uations is derived. In this model, there exist three kinds of equilibr ium states. The first is the zero shear state of the radial electric f ield; the second is the positive shear state of the radial electric fi eld; 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 s table states with the negative shear radial electric field are relevan t td: the behavior such as that exhibited by high (H) mode and by edge localized modes (ELMs), respectively. (C) 1997 American Institute of Physics.