Low-frequency microscopic stability analysis in fusion devices

A plasma confined in a fusion device is characterized by the presence of gradients in the equilibrium parameters, such as density, temperature, magnetic field, etc. Such gradients may then result in loss of equilibrium and escape of the plasma from the confinement system. Using a microscopic analysis, a review is presented of the low-frequency, gradient-driven instabilities in fusion devices, including both the shearless case (local approximation) and the case when magnetic shear is present. A detailed analysis of instabilities related to the tokamak configuration, such as trapped-particle modes, is also given. (author)