Guided by the recent experimental finding of the key role played by the ion heat channel in the transition from low (L) to high (H) confinement mode (Ryter et al 2014 Nucl. Fusion 54083003, Schmidtmayr et al 2018 Nucl. Fusion 58 056003), the present phenomenological model of the power threshold for the L-H transition is developed by combining the energy equipartition between electrons and ions, and the L-mode scaling of the energy confinement time. This heuristic model describes with continuity the transition of the power threshold from the low- to the high-density branches and clarifies the origin of the main dependence of the power threshold on the plasma current in the low density branch.
基于离子热通道在低约束模式（L）向高约束模式（H）转变中起关键作用的最新实验发现（Ryter等，2014，Nucl. Fusion 54083003；Schmidtmayr等，2018，Nucl. Fusion 58 056003），本文发展了L-H转变功率阈值的唯象模型，该模型结合了电子与离子之间的能量均分以及L模能量约束时间的定标。该启发式模型连续描述了从低密度分支到高密度分支的功率阈值转变，并阐明了低密度分支中功率阈值主要依赖等离子体电流的起源。