On the basis of an analysis of the ITER L-mode energy confinement database, two new scaling expressions for tokamak L-mode energy confinement are proposed, namely a power law scaling and an offset-linear scaling. The analysis indicates that the present multiplicity of scaling expressions for the energy confinement time τE in tokamaks (Goldston, Kaye, Odajima-Shimomura, Rebut-Lallia, etc.) is due both to the lack of variation of a key parameter combination in the database, fs = 0.32 R a−0.75 k0.5 ∼ A a0.25k0.5, and to variations in the dependence of τE on the physical parameters among the different tokamaks in the database. By combining multiples of fs and another factor, fq = 1.56 a2 kB/RIp = qeng/3.2, which partially reflects the tokamak to tokamak variation of the dependence of τE on q and therefore implicitly the dependence of τE on Ip and ne, the two proposed confinement scaling expressions can be transformed to forms very close to most of the common scaling expressions. To reduce the multiplicity of the scalings for energy confinement, the database must be improved by adding new data with significant variations in fs, and the physical reasons for the tokamak to tokamak variation of some of the dependences of the energy confinement time on tokamak parameters must be clarified.
基于对ITER L模能量约束数据库的分析，提出了两种用于托卡马克L模能量约束的新定标表达式，即幂律定标和偏移线性定标。分析表明，目前托卡马克能量约束时间τE的多种定标表达式（如Goldston、Kaye、Odajima-Shimomura、Rebut-Lallia等）之所以存在差异，既是因为数据库中的一个关键参数组合fs = 0.32 R−0.75 a0.75 k0.5 ∼ A0.25 a0.25 k0.5缺乏变化，也是因为不同托卡马克中τE对物理参数的依赖关系存在差异。通过将fs的倍数与另一个因子fq = 1.56 a2 k B / R I = qeng / 3.2（该因子部分反映了不同托卡马克中τE对q的依赖差异，从而隐含了τE对Ip和ne的依赖差异）相结合，所提出的两种定标表达式可以转换为与大多数常见定标表达式非常接近的形式。为了减少能量约束定标表达式的多样性，必须通过添加在fs方面具有显著变化的新数据来改进数据库，并且必须阐明不同托卡马克中能量约束时间对托卡马克参数某些依赖关系存在差异的物理原因。