著者

平野 洋一

出版者

社団法人 プラズマ・核融合学会

雑誌

プラズマ・核融合学会誌 = Journal of plasma and fusion research (ISSN:09187928)

巻号頁・発行日

vol.75, no.5, pp.614-630, 1999-05

参考文献数

60

被引用文献数

9 9

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Recent results of confinement studies and attempts to improve the confinement in reversed field pinch plasmas (RFP) are reviewed. Several scaling studies of RFP energy confinement time are summarized and the values of the confinement time of RFPs are compared with ITER−89P L-mode scaling. A new scaling law recently proposed is also described. Results of transport studies in RFPs are summarized and it is shown that the stochasticity of magnetic field lines caused by the magnetic fluctuations of dynamo action probably plays a dominant role in the core of RFP plasma. Recent Lundquist number scaling study for magnetic fluctuations is also described. Promising experimental and simulation results are introduced which are conducted to improve the RFP confinement. For examples, five-hold improvement of the energy confinement time is obtained in MST by driving the poloidal current in outer region with the pulsed poloidal current drive (PPCD). The increase of poloidal beta up to 20% is obtained in the Improved High Theta Mode in TPE−1RM20. Improved confinement by a flow shear is also observed in RFPs as in tokamaks and helical systems. Finally experimental and computational results are described which may indicate the bifurcation from the dynamo with multiple helical magnetic fluctuations to that with a single helical fluctuation through the increase of Prandtl number. In the case with a single helical fluctuation, the stochastic region caused by the over-lapping of magnetic islands can be reduced and the confinement degradation by the stochasticity of magnetic field lines may be avoided.