Plasma Equilibrium with Inner Separatrix in Tokamaks

Abstract

Several plasma equilibria with inner (current and magnetic) separatrices in a tokamak have been considered. Calculated and available experimental data for such equilibria have been compared. It is shown that a qualitative change in the equilibrium plasma configuration is possible at a small change in the inner plasma inductance in a tokamak. It is noted that an equilibrium solution is possible for some types of flux functions in the Grad–Shafranov equation, only if the plasma density at its boundary is nonzero. It is established that the formation of a natural poloidal divertor is determined not only by the \({{\beta }_{p}}\) value but also by the type of flux functions of the Grad–Shafranov equation. The possibility of the existence of equilibrium plasma configurations with magnetic axes located one above the other and the possibility of the existence of equilibrium plasma systems with many magnetic axes are shown.