The large tokamak JT-60: a history of the fight to achieve the Japanese fusion research mission

Fusion research was driven by the oil shocks in 1970's and the concern about climate change during 20th century. This paper addressed the scientific research history of JT-60, the tokamak that achieved record fusion performances and opened the way toward the continuous operation of a tokamak fusion reactor through its scientific discoveries. The paper also highlighted technical struggles to improve machine capabilities and to solve technical issues faced during the JT-60 project. The missions of JT-60 were to achieve equivalent energy break-even (Q = P-DT(equi.) / P-heat 1) and to establish a scientific basis for fusion reactor. The JT-60 made several modifications to reach equivalent break-even condition and continued efforts were made by the JT-60 team to solve critical technical issues during 23 years of research operation. Scientific success of JT-60 led to current ITER projects and the modification of JT-60 to a superconducting tokamak, JT-60SA. This paper is intended to be useful for the future researchers and managers of large-scale project by giving dynamical evolutions and highlighting key players. I dedicate this paper to Hiroshi Kishimoto, who made an outstanding contribution in managing the JT-60 research project.