Kim Eun-jin, Diamond P H
Department of Physics, University of California-San Diego, La Jolla, California 92093-0319, USA.
Phys Rev Lett. 2003 May 9;90(18):185006. doi: 10.1103/PhysRevLett.90.185006.
We elucidate the role of zonal flows in transient phenomena observed during L-H transition by studying a simple L-H transition model which contains the evolution of zonal flows, mean ExB flows, and the ion pressure gradient. Zonal flows are shown to trigger the L-H transition and cause time-transient behavior through the self-regulation of turbulence before a mean shearing, due to a steep pressure profile, secures a quiescent H mode. Surprisingly, this self-regulation lowers the power threshold for the ultimate transition to a quiescent H-mode state.
我们通过研究一个简单的从低约束模（L模）到高约束模（H模）转变模型来阐明带状流在L-H转变期间所观测到的瞬态现象中的作用，该模型包含带状流、平均ExB流以及离子压力梯度的演化。研究表明，带状流通过在平均剪切之前对湍流的自我调节来触发L-H转变并导致时间瞬态行为，这种平均剪切是由于陡峭的压力分布而产生的，它确保了一个静态的H模。令人惊讶的是，这种自我调节降低了最终转变为静态H模状态的功率阈值。
