TECHNICAL BACKGROUND AND PROGRAMMING CONSIDERATIONS This paperdescribes the modeling and simulation of the PF power system for the Tokamak Physics Experiment CI_X), I. Coupled EM Circuits which is requiredto supply pulsed DC current to the Poloidal Field (PF) superconducting coil system. An analytical model The PF coils, the plasma current, as well as the passive was developed to simulate the dynamics of the PF power structures(vacuum vessel, passive stabilizer, etc._, constitute system for any PF current scenario and thereby provide the coupled EM circuits in a tokamak. In the subject work, the basis for selection of PF circuit topology, in supportof the plasma currentwas modeled as a single filament placed at the major design goal of optimizing the use of the existing currentcentroid rather than the plasma center. Parametersof Tokamak Fusion Test Reactor (TFTR) facilities at the theplasma are assumed to be f'Lxed throughoutthe calculation. PrincetonPlasma Physics Lab (PPPL). The vacuum vessel is modeled as loop-segments coaxial with the PF coils. As a matterof programmingconvenience, other