The isotope dependence of plasma transport will have a significant impact on the performance of future D-T experiments in JET and ITER and eventually on the fusion gain and economics of future reactors. In preparation for future D-T operation on JET, dedicated experiments and comprehensive transport analyses were performed in H, D and H-D mixed plasmas. The analysis of the data has demonstrated an unexpectedly strong and favourable dependence of the global confinement of energy, momentum and particles in ELMy H-mode plasmas on the atomic mass of the main ion species, the energy confinement time scaling as tau(E) similar to A(0.5) (Maggi et al., Plasma Phys. Control. Fusion, vol. 60, 2018, 014045; JET Team, Nucl. Fusion, vol. 39, 1999, pp. 1227-1244), i.e. opposite to the expectations based only on local gyro-Bohm (GB) scaling, tau(E) similar to A(-0.5), and stronger than in the commonly used H-mode scaling for the energy confinement (Saibene et al., Nucl. Fusion, vol. 39, 1999, 1133; ITER Physics Basis, Nucl. Fusion, vol. 39, 1999, 2175). The scaling of momentum transport and particle confinement with isotope mass is very similar to that of energy transport. Nonlinear local GENE gyrokinetic analysis shows that the observed anti-GB heat flux is accounted for if collisions, ExB shear and plasma dilution with low-Z impurities (Be-9) are included in the analysis (E and B are, respectively the electric and magnetic fields). For L-mode plasmas a weaker positive isotope scaling tau(E) similar to A(0.14) has been found in JET (Maggi et al., Plasma Phys. Control. Fusion, vol. 60, 2018, 014045), similar to ITER97-L scaling (Kaye et al., Nucl. Fusion, vol. 37, 1997, 1303). Flux-driven quasi-linear gyrofluid calculations using JETTO-TGLF in L-mode show that local GB scaling is not followed when stiff transport (as is generally the case for ion temperature gradient modes) is combined with an imposed boundary condition taken from the experiment, in this case predicting no isotope dependence. A dimensionless identity plasma pair in hydrogen and deuterium L-mode plasmas has demonstrated scale invariance, confirming that core transport physics is governed, as expected, by the 4 dimensionless parameters rho*, nu*, beta, q (normalised ion Larmor radius, collisionality, plasma pressure and safety factor) consistently with global quasi-linear gyrokinetic TGLF calculations (Maggi et al., Nucl. Fusion, vol. 59, 2019, 076028). We compare findings in JET with those in different devices and discuss the possible reasons for the different isotope scalings reported from different devices. The diversity of observations suggests that the differences may result not only from differences affecting the core, e.g. heating schemes, but are to a large part due to differences in device-specific edge and wall conditions, pointing to the importance of better understanding and controlling pedestal and edge processes.

中文翻译：

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托卡马克中能量、动量和粒子约束的同位素依赖性

等离子体传输的同位素依赖性将对未来 JET 和 ITER 中的 DT 实验的性能产生重大影响，并最终影响未来反应堆的聚变增益和经济性。为了准备未来在 JET 上进行 DT 操作，在 H、D 和 HD 混合等离子体中进行了专门的实验和综合传输分析。数据分析表明，ELMy H 模式等离子体中能量、动量和粒子的全局限制对主要离子种类的原子质量具有出乎意料的强烈和有利的依赖性，能量限制时间缩放为 tau(E)到 A(0.5) (Maggi et al., Plasma Phys. Control. Fusion, vol. 60, 2018, 014045; JET Team, Nucl. Fusion, vol. 39, 1999, pp. 1227-1244)，即与仅基于局部陀螺-玻姆 (GB) 缩放的预期，tau(E) 类似于 A(-0.5)，并且强于能量限制的常用 H 模式缩放（Saibene 等人，Nucl. Fusion，第 39 卷，1999 年，1133 年；ITER 物理基础，Nucl . Fusion, vol. 39, 1999, 2175)。同位素质量的动量传输和粒子约束的缩放与能量传输的缩放非常相似。非线性局部 GENE 陀螺动力学分析表明，如果分析中包括碰撞、ExB 剪切和具有低 Z 杂质 (Be-9) 的等离子体稀释（E 和 B 分别是电和磁场）。对于 L 型等离子体，在 JET 中发现了类似于 A(0.14) 的较弱正同位素标度 tau(E)（Maggi 等人，Plasma Phys. Control. Fusion, vol. 60, 2018, 014045），类似于 ITER97 -L 缩放（Kaye 等人，Nucl. Fusion，第 37 卷，1997 年，1303 年）。在 L 模式下使用 JETTO-TGLF 的通量驱动准线性陀螺流体计算表明，当刚性传输（通常是离子温度梯度模式的情况）与从实验中获取的强加边界条件相结合时，不会遵循局部 GB 缩放，在这种情况下预测没有同位素依赖性。氢和氘 L 型等离子体中的无量纲恒等等离子体对显示出尺度不变性，证实核心传输物理如预期的那样受 4 个无量纲参数 rho*、nu*、β、q（归一化离子拉莫尔半径、碰撞性）控制、等离子体压力和安全系数）与全局准线性陀螺动力学 TGLF 计算一致（Maggi 等人，Nucl. Fusion，第 59 卷，2019 年，076028）。我们将 JET 中的发现与不同设备中的结果进行比较，并讨论不同设备报告的同位素比例不同的可能原因。观察结果的多样性表明，差异可能不仅源于影响核心的差异，例如加热方案，而且在很大程度上是由于特定于设备的边缘和墙壁条件的差异，表明更好地理解和控制基座的重要性和边缘工艺。