New Adaptive Grid Plasma Evolution Code SPIDER A.A.Ivanov 1

Non-linear time-evolution codes are essential tools for modeling of existing and future tokamak experiments. Now there are several well known free-boundary plasma equilibrium evolution codes, such as DINA [1], PET [2] and TSC [3]. In all existing evolution codes 2D equilibrium problem is solved on rectangular grid and special mapping technique is required to solve 1D transport and magnetic field diffusion equations self-consistently with 2D free-boundary equilibrium. To achieve high accuracy of simulations a lot of iterations between solutions of the 2D equilibrium problem and the set of 1D equations are required, that leads to a substantial increase of the computational time. Another problem arises in case of plasma equilibrium with high edge or non-monotonic plasma current density. The size of the rectangular mesh needed to resolve such equilibrium features should be increased several times leading to an order of magnitude increase in the time of simulation. A NEW nonlinear time-evolution free-boundary equilibrium code SPIDER has been developed, in which 2D equilibrium problem is solved using adaptive grid method. As a result the coordinates of magnetic surfaces are obtained and no additional mapping i