A filament code for tokamak axisymmetric stability

A program for simulating the axisymmetric time evolution of plasma position within a tokamak is described. The conductors in the system are represented by sets of toroidal filaments which are given the relevant electrical and geometrical properties. The plasma position is determined by force balance, and a matrix equation is solved for the resulting filament currents. The program theory and structure together with some comparisons with analytical theory are presented. Also, to illustrate the capability of the code, some results that have contributed to the design of a possible new system of fast active plasma control are described. (orig.)