A predictive model for the tokamak density limit. (28th July 2016)

• Record Type: Journal Article
• Authors: Teng, Q.; Brennan, D.P.; Delgado-Aparicio, L.; Gates, D.A.; Swerdlow, J.; White, R.B.
• Is Part Of: Nuclear fusion. Volume 56:Number 10(2016:Oct.)
• Publication Date: 2016-07-28
• Subjects: density limit -- tearing mode -- impurity radiation; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/0029-5515/56/10/106001
• Languages: English
• ISSNs: 0029-5515

Abstract

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 a local edge limit and weakly dependent on impurity densities. Results are robust to a substantial variation in model parameters within the range of experiments.