Reynolds stress is a key facet of turbulence self-organization. In the magnetized plasmas of controlled fusion devices, the zonal flows that are driven by the averaged Reynolds stress modify the confinement performance. We address this problem with full-f gyrokinetic simulations of ion temperature gradient-driven turbulence. From the detailed analysis of the three-dimensional electric potential and transverse pressure fields, we show that the diamagnetic contribution to the Reynolds stress—stemming from finite Larmor radius effects—exceeds the electrostatic contribution by a factor of about two. Both contributions are in phase, indicating that pressure does not behave as a passive scalar. In addition, the Reynolds stress induced by the electric drift velocity is found to be mainly governed by the gradient of the phase of the electric potential modes rather than by their magnitude. By decoupling Reynolds stress drive and turbulence intensity, this property indicates that a careful analysis of phase dynamics is crucial in the interpretation of experiments and simulations.

雷诺应力是湍流自组织的一个关键方面。在受控聚变装置的磁化等离子体中，由平均雷诺应力驱动的带状流动改变了限制性能。我们用full- f来解决这个问题离子温度梯度驱动湍流的陀螺动力学模拟。通过对三维电势场和横向压力场的详细分析，我们表明对雷诺应力的反磁性贡献（源自有限拉莫尔半径效应）超过静电贡献约两倍。两个贡献是同相的，表明压力不表现为被动标量。此外，发现由电漂移速度引起的雷诺应力主要受电势模式的相位梯度而不是它们的大小控制。通过将雷诺应力驱动和湍流强度解耦，这一特性表明对相动力学的仔细分析对于实验和模拟的解释至关重要。