Model for Pedestal Transport Based on Suppression of Anomalous Transport Using ωE ×B Flow Shear and Magnetic Shear

Abstract

A model for describing a pedestal transport in H -mode tokamak plasmas is developed and tested in BALDUR integrated predictive modelling code. The transport model is calculated based on the suppression of an anomalous core transport due to the ω E × B flow shear and magnetic shear. Because of the reduction of transport in the edge region, the pedestal can be formed and evolved. In this work, an anomalous transport is computed using a semi-empirical mixed Bohm/gyro-Bohm anomalous core transport model. The BALDUR code with both core and pedestal transport is used to simulate the time evolution of plasma current, ion and electron temperature, and particle and impurity density profiles for 10 DIII-D H -mode discharges in various plasma scenarios (i.e., gyro-radius scan, density scan, power scan, and elongation scan). It is found that the formation of the pedestal can be observed in all simulations, in which the L – H transition in the simulations is consistent with the L – H transition power threshold model. ...