A Predictive Model for the Tokamak Density Limit
Authors: Q. Teng, D.P. Brennan, L.
Delgado-Aparicio, D.A. Gates, J. Swerdlow, R.B. White
Abstract: The Greenwald density limit, found in all
tokamak experiments, is reproduced for the first time using a
phenomenologically correct model with parameters in the range of
experiments. A simple model of equilibrium evolution and local
power balance inside the island has been implemented to calculate
the radiation-driven thermo-resistive tearing mode growth and
explain the density limit. Strong destabilization of the tearing
mode due to an imbalance of local Ohmic heating and radiative
cooling in the island predicts the density limit within a few
percent. The density limit is found to be weakly dependent on
impurity densities. Results are robust to a substantial variation
in model parameters within the range of experiments.
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