The SPIDER code — free boundary tokamak plasma quasi equilibrium evolution under condition of magnetic field diffusion solver

Quasi-equilibrium evolution of tokamak plasma with taking into account the magnetic field diffusion in a resistive plasma and eddy currents in poloidal field coils and passive conductors is described by a set of nonlinear equations: 2D free boundary plasma equilibrium equation, 1D magnetic field diffusion equation and circuit equations for eddy currents. The set of differential equations with initial and boundary conditions is approximated by a finite-difference scheme. The discrete problem is solved using iterative methods. The results of simulations are presented.