Boundary element analysis of free boundary field-reversed configurations

Field-reversed configuration (FRC) plasmas are governed by the nonlinear Grad-Shafranov equation and it is difficult to analyze this equation for FRC devices by using domain-type methods because the plasma boundary is a free boundary. In the present work, the authors solve the Grad-Shafranov equation using the boundary element method (BEM) in order to study equilibrium configurations for the FRC with a free boundary. In the numerical analysis, the simple iterative method is used to obtain nonlinear solutions of the equation. As a result it is found that a stable solution can only exist for parameter K, which denotes the ratio of the electromagnetic force to the plasma pressure. In addition, the equilibrium configuration is calculated by using BEM for the rigid drift model and the slitted model