Core transport studies in fusion devices

Kapitel i bok, 2010

Comprehensive first principles modelling of fusion plasmas is a numerically challenging: the complicated magnetic geometry and long range electromagnetic interactions between multiple species introduce complex collective behaviour in the plasma. In addition, steep density and temperature gradients combined with an inhomogeneous magnetic field drives instabilities, resulting in non-linear dynamics and turbulence. The turbulence in magnetically confined fusion plasmas has important and non-trivial effects on the quality of the energy confinement. These effects are hard to make a quantitative assessment of analytically. The problem investigated in this article is the transport of energy and particles, in particular impurities, in a Tokamak plasma. Impurities from the walls of the plasma vessel cause energy losses if they reach the plasma core. It is therefore important to understand the transport mechanisms to prevent impurity accumulation and minimize losses. This is an area of research where turbulence plays a major role and is intimately associated with the performance of future fusion reactors, such as ITER.