ABSTRACT
This chapter provides the general results of the equilibrium theory of a plasma in toroidal confinement systems necessary for constructing the stability theory and presents these results using an example of circular-cylinder geometry. In principle, all the coordinate functions describing the physical quantities can be presented as a sum of oscillating and non-oscillating parts. The chapter introduces two surface functions: transverse and longitudinal magnetic fluxes. It suggests that the ratio of the radial derivatives of these functions is the rotation ratio, while the inverse ratio of these derivatives is the safety factor. The chapter provides a general description of the isotropic-plasma equilibrium, and describes several surface functions: plasma pressure, toroid volume, and transverse and longitudinal current fluxes. It discusses effects related to the metric oscillations, and deals with the cylindrical case, the electric-current density has an oscillating part connected with the plasma pressure and oscillations of the metric-tensor determinant.
