AI 中文总结
本研究通过 GENE 和 CGYRO 代码的模拟与基准测试，揭示托卡马克电磁微湍流对电流的径向输运特性，为高β托卡马克等离子体的旋转、电流与安全因子耦合演化提供了关键依据。
AI 中文摘要
环形角动量的湍流输运决定了托卡马克等离子体的旋转轮廓，进而影响其约束性与稳定性。其中电子的贡献还有额外影响：即使是适度的电子动量通量，也可能对应可观的环形电流湍流通量，其散度原则上可改变安全因子轮廓。本文通过非线性 gyrokinetic 模拟表明，电磁波动会定性改变湍流动量输运。在微撕裂模驱动的湍流中，总动量输运相对于热输运效率较低，但与湍流麦克斯韦应力相关的电子贡献主导了动量通量；该贡献超过了湍流电流重分布所需的估计尺度，足以与维持自举电流的碰撞过程相抗衡。在考虑的动力学气球模驱动湍流情形中，动量输运更强，且仍由静电离子贡献主导；不过，保留麦克斯韦应力对电子动量通量超过该自举基准尺度至关重要。为开展本研究，我们在 gyrokinetic 代码 GENE 和 CGYRO 中独立实现了完整的电磁动量通量诊断，并通过线性和非线性跨代码基准测试验证了其有效性。综上，这些结果表明，电磁动量输运可能对高β托卡马克等离子体中旋转、电流与安全因子轮廓的耦合演化具有重要意义。
英文摘要
The turbulent transport of toroidal angular momentum helps determine the rotation profiles of tokamak plasmas, and thereby their confinement and stability. The electron contribution therein has an additional consequence: even a modest electron momentum flux can correspond to a substantial turbulent flux of toroidal current, whose divergence could in principle modify the safety-factor profile. Here, using nonlinear gyrokinetic simulations, we show that electromagnetic fluctuations qualitatively alter turbulent momentum transport. In microtearing-mode-driven turbulence, the total momentum transport is inefficient relative to that of heat, yet an electron contribution associated with the turbulent Maxwell stress dominates the momentum flux. We show that this contribution exceeds an estimated scale required for turbulent current redistribution to compete with the collisional processes maintaining the bootstrap current. In the case of kinetic-ballooning-mode-driven turbulence considered, the momentum transport is found to be stronger and remains dominated by the electrostatic ion contribution; nevertheless, retaining the Maxwell stress is essential for the electron momentum flux to exceed this bootstrap-based reference scale. To enable this study, we independently implemented complete electromagnetic momentum-flux diagnostics in the gyrokinetic codes GENE and CGYRO, and verified them through linear and nonlinear cross-code benchmarks. Taken together, these results suggest that electromagnetic momentum transport may potentially be important for the coupled evolution of the rotation, current, and safety-factor profiles in high-beta tokamak plasmas.
