Design of a Homopolar Generator Power Supply System for the Ignitex Experiment

The fusion ignition experiment IGNITEX [l] is based on the concept of a tokomak operating at very high magnetic fields. The toroidal field (TF) and the poloidal field (PF) magnet systems are made of single turn coils which provide the capability to produce very high magnetic fields (20 T) and induce very high plasma currents (12 MA). These magnet systems have very low impedances which impose rather strict constraints on the power supply system in terms of energy (12 GJ), current (150 MA), voltage (10 V), and pulse length (10 V). In addition, the power supply system should comply with the general IGNITEX emphasis on simplicity, reliability, and low cost. A set of homopolar generators (HPGs) can meet these requirements. The characteristics of the HPGs for the proposed TF and PF magnet systems, materials, fabrication procedures, and technologies to be employed in the construction of the generators are described. A preliminary mode of operation for the generators and associated circuit schemes are given. Auxiliary systems needed for operation of the system are described and estimates for the grid power requirements for the IGNITEX facility are obtained and analyzed. A modular approach for the design and construction of small and large versions of the IGNITEX experiment is presented. Although no generator exists that meets the requirements of the IGNITEX experiment, the technologies needed for it have been demonstrated. The construction and operation of a full size, 1 GJ, HPG module for the IGNITEX demonstration baa been proposed. The technological basis, objectives, schedule, and coats of the demonstration program are presented. This represents the second element of the Ignition Technology Demonstration (ITD) program associated with the IGNITEX project (the first element of the ITD program is presented in companion papers by M. Werst, [2] and K. T. Hsieh, [3] at this Symposium).