IONIZATION-INSTABILITY AND SELF-CONSISTENT MODEL OF ANOMALOUS TRANSPORT AT THE PLASMA EDGE

Drift waves are destabilized by the ionization of neutrals at the plas ma edge and stabilized by electron Landau damping. The transport equat ions, the ''Ansatz'' Q(e) proportional to Gamma(e)*T-e (where Q(e)*, respectively Gamma(e), is the electron heat, respectively the particl e flux) and the mode's marginal stability condition form a self-contai ned set for the determination of the edge temperature and density prof iles. The electron temperature at the separatrix and the particle conf inement time are also obtained and compared to experimental values; th e particle confinement time, in particular, is very close to the heuri stic energy confinement time of Kaye-Goldston. If it is further assume d that energy and particle exhausts are along the open field lines of a magnetic island belt associated with the instability and intersectin g the last closed equilibrium magnetic surface, then the theory provid es an estimate of the level of the magnetic component of the mode, whi ch is also compared to some experimental data, and a scenario for equi librium bifurcation. Independently from the details of the transport m echanism, the bifurcation can, quite generally, be associated with the positive (proportional to T-e(3/2)) dependence of electron Landau dam ping on temperature.