Moyer R A, Tynan G R, Holland C, Burin M J
Mechanical and Aerospace Engineering Department, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.
Phys Rev Lett. 2001 Sep 24;87(13):135001. doi: 10.1103/PhysRevLett.87.135001. Epub 2001 Sep 4.
The nonlinear coupling between small scale high-frequency turbulence and larger scale lower-frequency fluctuations increases transiently in transitions to improved confinement in the DIII-D tokamak. This increase starts before the rapid turbulence suppression and E x B shear-flow development in the region that becomes the H-mode transport barrier/shear flow region. After the transition, the coupling returns to L-mode levels. These results are consistent with expectations for spontaneous transitions to improved confinement triggered by a turbulence-driven sheared flow.
在DIII-D托卡马克装置向改善约束转变的过程中，小尺度高频湍流与大尺度低频涨落之间的非线性耦合会短暂增强。这种增强在快速湍流抑制和成为H模输运垒/剪切流区域的区域内的E×B剪切流发展之前就已开始。转变之后，耦合会回到L模水平。这些结果与由湍流驱动的剪切流引发的向改善约束的自发转变的预期相符。
