Present status of fusion researches in USA, 4. Current status of fusion research at Plasma Physics Laboratory of Princeton University

25 years have elapsed since nuclear fusion was published at the second Geneva conference in 1958. During this period, the Plasma Physics Laboratory of Princeton University has achieved the central role in the research on toroidal system nuclear fusion devices. Also the experiment of the large tokamak TFTR started from December, 1982, recorded the longest containment time of 200 ms as the initial data, and toroidal devices look to approach one step close to the scientific verification experiment (Q = 1) of reactors. In the PPPL, in order to perfect the basis required for the realization of nuclear fusion reactors, the experimental and theoretical developments have been carried out. Plasma containment experiment has been advanced successively from stellarator through internal conductor type to tokamak, and in plasma heating, ion cyclotron heating, fast neutral particle injection heating and low region hybrid heating were successfully carried out. As the experimental apparatuses, that for poloidal divertor experiment, Princeton large torus, tokamak fusion test reactor (TFTR) and S-1 spheromak are described. From the theories developed recently, bean type tokamak, heliac-stellarator and nuclear fusion reaction utilizing μ-mesons and nuclear spin are explained. (Kako, I.)