A Riemannian geometrical method to classify tearing instabilities in plasmas

Abstract

Riemannian geometrical tools, such as Ricci collineations and Killing symmetries, so often used in Einstein general theory of gravitation are here applied to plasma physics to build magnetic surfaces from Einstein plasma metrics used in tokamak devices. It is shown that the Killing symmetries are constrains the Einstein magnetic surfaces while the Killing vectors are built in terms of the displacement of the toroidal surface. The pressure is computed by applying these constraints to the pressure equations in tokamaks. A method, based on the sign of the only nontrivial constant Riemann curvature component, is suggested to classify tearing instability. Throughout the computations two approximations are considered: The first is the small toroidality and the other is the small displacement of the magnetic surfaces as Einstein spaces.