Characterization of electrostatic turbulent fluxes in tokamak edge plasmas

A parametrization is presented for the transport from electrostatic turbulence in tokamak edge plasmas. Employing a nonlinear drift wave turbulence simulation, transport coefficients are obtained as functions of a density gradient, temperature gradients, and an external E×B shear parameter. An external radial electric field, Er, is passed to the turbulence model as a background E×B shear flow which suppresses the radial flux together with the Reynolds stress induced electric fields. In a multidimensional parameter space, the transport coefficients exhibit a nonmonotonic dependence on the density and temperature gradients that is unique to the low to high confinement transition.

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