A Quarter-century of Fusion Superconducting Magnet Development

Fusion supercondcucting magnet development in Japan started in 1976 as it also did in Western countries. After a quarter-century, 13T was successfully achieved in a bore of 2m and in pulsed operation for plasma current transformer in JAERI (Japan Atomic Energy Research Institute). Thus it is a good occasion to describe the chronological evolution of the development work in order to transmit this history to the 21st century. After explanation of the Japanese circumstances around 1970 in cryogenic and high field technologies, the paper introduces the technical report, published in 1977 by section of superconducting magnet of the Fusion Council, on the development of tokamak magnet system for experimental reactor. The each decision making of every step in the real projects evolved later is described here. The international collaborations and the application of resulting techniques to new facilities in other laboratories are represented.