RAPID: Potential Vorticity Mixing Experiments on COMPASS Plasma Device

该奖项将支持一项基于等离子体的实验性研究，研究旋转系统中的小尺度湍流如何产生大尺度流动。在旋转的恒星和气态巨行星中，在旋转的类地行星的海洋和熔融的核心中，在具有强磁场的等离子体中，类流体介质的行为受到与介质本身的整体自转相关的力的深刻影响。这些力量导致了有序的、缓慢变化的剪切流的出现。理论预测，所有这样的系统都有相同的切变流动的潜在来源，通过一个被称为位涡的量。在旋转的流体中，例如在地球物理、行星和恒星系统中，位涡是由局部流体涡度和行星自转本身的组合给出的。该奖项支持的实验研究将首次尝试直接测试势涡在湍流磁化等离子体中剪切流的形成中所起的作用，并将对未来聚变能源的发展产生更广泛的影响。这项实验将在捷克共和国的COMPASS等离子体装置上进行，随后的数据分析将由高年级的本科生进行。该项目将对理论预测进行实验测试，该理论预测，由于强大的洛伦兹力的影响，在磁化的环形等离子体中会出现湍流产生的剪切流，因此遵循类似于行星和恒星大气中由于科里奥利力的影响而形成剪切流的基本非线性动力学。如果这个实验证明了这一点，它将在这两个看似不同的物理系统之间提供强大的联系。如果结果表明预测实际上是不正确的，那么它将迫使人们从根本上重新思考这一理论。无论哪种情况，结果都将影响我们对湍流流体和等离子体系统中自组织过程的理解。该奖项由物理部支持，并得到多学科活动办公室和国际科学与工程办公室的额外支持。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award will support an experimental plasma-based study of how large-scale flows may emerge from small-scale turbulence in rotating systems. The behavior of fluid-like media in rotating stars and gas giant planets, in the oceans and molten cores of rotating Earth-like planets, and in plasmas with strong magnetic fields is profoundly affected by the forces associated with the overall rotation on the medium itself. These forces lead to the emergence of well ordered, slowly varying sheared flows. Theory predicts that all such systems share the same underlying origin of the sheared flows via a quantity known as the potential vorticity. In a rotating fluid, for example in geophysical, planetary and stellar systems, the potential vorticity is given by a combination of the local fluid vorticity and the planetary rotation itself. The experimental study supported by this award will make the first-ever attempt to directly test the role that potential vorticity plays in the formation of sheared flows in turbulent magnetized plasmas and will have broader implications for future development of fusion energy sources. The experiment will be performed on the COMPASS plasma device in the Czech Republic, and the subsequent data analysis will be carried out by upper-division undergraduate students.This project will provide an experimental test of the theoretical prediction that turbulence-generated shear flows appear in magnetized toroidal plasmas due to the effects of a strong Lorentz force, and as such follow similar underlying nonlinear dynamics to that responsible for shear flow formation found in the atmospheres of planets and stars due to the effects of the Coriolis force. Should this experiment demonstrate that this is the case, it would provide a strong link between these two seemingly disparate physical systems. Should the result show that the prediction is in fact incorrect, it would then force a fundamental rethinking of the theory. In either case, the outcome will impact our understanding of self-organization processes in turbulent fluid and plasma systems. This award is supported by the Division of Physics with additional support from the Office of Multidisciplinary Activities and the Office of International Science and Engineering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.