ITER plasma equilibrium and poloidal field system design

Several poloidal field coil design issues are identified when assessing the benefits of high plasma elongaton in an ITER device. Among these are the sensitivity of PF ampere-turens and coil energy to specific constraints on the plasma shape and profiles and the optimal placement of PF coils subject to assumed operating scenarios. Two versons of free boundary equilibrium codes presently under development at the Oak Ridge National Laboratory (ORNL), HEQ and VEQ, are used to solve several PF design problems related to these issues. Recent efforts have been directed toward problems in the analysis of highly elongated, magnetically-limited plasmas, such as X-point and divertor strike-point placement and control. In this report, we describe the capabilities of HEQ and discuss the major options available to the user. Applications of HEQ and VEQ in the area of plasma elongation tradeoff studies are presented. 8 refs., 4 figs., 4 tabs