Numerical modeling of the plasma response to local cooling

Thermal instabilities can lead to a sudden drop of local plasma temperature by orders of magnitude and numerical modeling of the global plasma response to such phenomena is performed. An approach to operate with the plasma heat conduction κ, being a non-linear function both of the plasma temperature and of its gradient, if the heat flux limit is taken into account, is developed. It is demonstrated that the deviation of κ from Spitzer-Härm approximation normally assumed is essential to explain experimental findings by massive gas injection experiments carried out to mitigate plasma disruptions in tokamaks