The multi-machine International Tokamak Physics Activity (ITPA) Global H-mode Confinement Database has been upgraded with new data from JET with the ITER-like wall and ASDEX Upgrade with the full tungsten wall. This paper describes the new database and presents results of regression analysis to estimate the global energy confinement scaling in H-mode plasmas using a standard power law. Various subsets of the database are considered, focusing on type of wall and divertor materials, confinement regime (all H-modes, ELMy H or ELM-free) and ITER-like constraints. Apart from ordinary least squares (OLS), two other, robust regression techniques are applied, which take into account uncertainty on all variables. Regression on data from individual devices shows that, generally, the confinement dependence on density and the power degradation are weakest in the fully metallic devices. Using the multi-machine scalings, predictions are made of the confinement time in a standard ELMy H-mode scenario in ITER. The uncertainty on the scaling parameters is discussed with a view to practically useful error bars on the parameters and predictions. One of the derived scalings for ELMy H-modes on an ITER-like subset is studied in particular and compared to the IPB98(y, 2) confinement scaling in engineering and dimensionless form. Transformation of this new scaling from engineering variables to dimensionless quantities is shown to result in large error bars on the dimensionless scaling. Regression analysis in the space of dimensionless variables is therefore proposed as an alternative, yielding acceptable estimates for the dimensionless scaling. The new scaling, which is dimensionally correct within the uncertainties, suggests that some dependencies of confinement in the multi-machine database can be reconciled with parameter scans in individual devices. This includes vanishingly small dependence of confinement on line-averaged density and normalized plasma pressure (β), as well as a noticeable, positive dependence on effective atomic mass and plasma triangularity. Extrapolation of this scaling to ITER yields a somewhat lower confinement time compared to the IPB98(y, 2) prediction, possibly related to the considerably weaker dependence on major radius in the new scaling (slightly above linear). Further studies are needed to compare more flexible regression models with the power law used here. In addition, data from more devices concerning possible ‘hidden variables’ could help to determine their influence on confinement, while adding data in sparsely populated areas of the parameter space may contribute to further disentangling some of the global confinement dependencies in tokamak plasmas.

多机国际托卡马克物理活动 (ITPA) 全球 H 模式约束数据库已升级，其中包含来自具有类似 ITER 壁的 JET 和具有完整钨壁的 ASDEX 升级的新数据。本文介绍了新数据库并介绍了回归分析的结果，以使用标准幂律估计 H 模式等离子体中的全局能量限制标度。考虑了数据库的各种子集，重点关注壁和偏滤器材料的类型、限制机制（所有 H 模式、ELMy H 或无 ELM）和 ITER 类约束。除了普通最小二乘法 (OLS) 之外，还应用了另外两种稳健的回归技术，它们考虑了所有变量的不确定性。来自单个设备的数据的回归表明，一般来说，在全金属器件中，对密度和功率衰减的限制依赖性最弱。使用多机缩放，可以预测 ITER 中标准 ELMy H 模式场景中的限制时间。讨论了缩放参数的不确定性，以期获得关于参数和预测的实际有用的误差线。特别研究了类 ITER 子集上 ELMy H 模式的导出缩放比例之一，并将其​​与工程和无量纲形式的 IPB98(y, 2) 限制缩放比例进行了比较。这种从工程变量到无量纲量的新标度的转换被证明会导致无量纲标度上的大误差条。因此，提出了无量纲变量空间中的回归分析作为替代方案，为无量纲缩放产生可接受的估计。新的缩放在不确定性范围内在维度上是正确的，这表明多机数据库中的某些限制相关性可以与单个设备中的参数扫描相协调。这包括限制对线平均密度和归一化等离子体压力的极小依赖性（β )，以及对有效原子质量和等离子体三角形的显着正相关性。与 IPB98(y, 2) 预测相比，将此缩放比例外推到 ITER 会产生略低的限制时间，这可能与新缩放比例（略高于线性）中对主半径的依赖性相当弱有关。需要进一步研究将更灵活的回归模型与此处使用的幂律进行比较。此外，来自更多设备的关于可能的“隐藏变量”的数据有助于确定它们对约束的影响，同时在参数空间的人口稀少的区域添加数据可能有助于进一步解开托卡马克等离子体中的一些全局约束依赖性。