A simple method of estimating ampere-turns in equilibrium coils

It is important in the design field of the tokamak machine to estimate coil currents for obtaining a plasma with required shape and physical parameters. The equilibrium analysis code for this use has already been developed in the JAERI, but usually it requires lengthy cpu time for the calculation. The code presented in this report, however, can deal with this problem in a simplified manner in which plasma current distribution is replaced to a set of several line currents. The magnetic field configuration produced by the equilibrium coil currents, which were obtained by using this code, are in good agreement with the equilibrium analysis result, hence this code showed to be a simple and very useful code for obtaining equilibrium coil currents. It is expected in the future that this code will be available for a fast analysis of the experiments, for example, Doublet III experiments. (author)