Non-linear magnetohydrodynamic hybrid simulations of the stability in tokamaks

Abstract

Plasma physics plays a fundamental role in fusion technology research. However, the main equations governing the plasma dynamics, Navier-Stokes coupled with Maxwell equations, have challenges such as non-linearity and multiple coupling among all the evolving properties. Thus, any analytical study has been reduced to linearized models, which can not properly reproduce the plasma behavior. These simple analytical models cannot fully reproduce an important and current drawback in fusion devices, i.e., plasma instabilities in tokamaks. Instabilities represent a non-negligible contribution to the loss of plasma confinement. Consequently, they limit the fusion energy release and also represent a source of material damage. Understanding, predicting and, eventually, mitigating these instabilities is an open research line within the plasma and fusion community. Accordingly, these instability studies should be carried out from both experimental and theoretical points of view, obtaining, in the theoretical approach, analytical results from equations and finally, solving numerically the plasma dynamics. This approach is followed in this work in order to study one particular type of instability, Toroidal Alfvén Eigenmode, TAE, giving a physical and mathematical background of its origin and carrying out several numerical simulations of the plasma dynamics. To study these instabilities, a realistic geometry has been developed during this work. The properties of the simulated losses are studied and correlated with the detection of the TAE instabilities inside the plasma.