Equation of State for Hydrodynamic Compression in Turbulent Z-pinch

该项目研究了将能量储存在湍流状漩涡中的可能性，压缩这些漩涡以进一步增加湍流能量。 这种可能性的意义在于，涡旋中的能量与随机能量的作用不同，因为相邻的分子倾向于向同一方向移动。 这种可能性在电离气体，等离子体中特别重要。首先，等离子体在压缩的时间尺度上可以是无粘性的，例如在某些分子云中自然发生的，或者在实验室中，在Z箍缩中，从而能够增加湍流能量。 其次，等离子体中有一些重要的过程，如辐射或核聚变，其效率高度依赖于这种相对运动。 一个恰当的例子是Z箍缩，这是一个圆柱形等离子体装置，其中沿轴向方向流动的电流产生径向压缩等离子体的磁场。 最近在魏茨曼科学研究所获得的光谱数据表明，Z箍缩中的能量可以由流体动力学湍流涡的运动所支配。以前已经表明，湍流涡能量的自洽解释导致停滞Z箍缩数据具有更大的一致性。 本项目的一个方面是使用这种方法来发展一个压缩湍流的准状态方程。 也有人预测，在压缩下，等离子体突然变得粘稠，因此可能会有湍流能量突然灾难性地释放成随机离子能量，从而突然启用依赖于热运动的过程。因此，该项目的第二个方面是探索这种奇怪效应的后果，这种效应发生在等离子体中，而不是中性气体中，以及探索这种效应如何在各种实验条件下受到影响。 这项工作将涉及普林斯顿大学和以色列魏茨曼科学研究所之间的合作，并将在NSF和美国-以色列两国科学基金会之间的研究合作谅解备忘录的保护下进行。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

This project investigates the speculative possibility of storing energy in turbulent fluid-like eddies, compressing these eddies so as to further increase the turbulent energy. The significance of this possibility is that energy in eddies acts differently than random energy because neighboring molecules tend to move in the same direction. This possibility can be particularly important in an ionized gas, a plasma. First, plasma can be inviscid on the time scales of compression, such as occurs naturally in certain molecular clouds or, in the laboratory, in Z-pinches, thereby enabling the increase of turbulent energy. Second, there are important processes in plasma, such as radiation or nuclear fusion, whose efficiency is highly dependent on this relative motion. A case in point is the Z-pinch, which is a cylindrical plasma device where current running in the axial direction produces a magnetic field that compresses plasma radially. Recent spectroscopic data taken at the Weizmann Institute of Science suggests that the energy in a Z-pinch can be dominated by the motion of hydrodynamic turbulent eddies.It has been previously shown that self-consistent accounting for the turbulent eddy energy leads to greater consistency in the stagnation Z-pinch data. One aspect of the present project is to use this approach to develop a quasi equation of state for compressing turbulence. It was also predicted that, under compression, plasma abruptly becomes viscous, so that there can be a sudden catastrophic release of the turbulent energy into random ion energy, thereby suddenly enabling processes that rely on thermal motion. Thus, a second aspect of the project is to explore both the ramifications of this curious effect, which occurs in plasma but not neutral gas, as well as to explore how this effect may be affected under a variety of experimental conditions. This work will involve collaboration between Princeton University and the Weizmann Institute of Science in Israel, and will be performed under the umbrella of the Memorandum of Understanding on Research Cooperation between NSF and the US-Israel Binational Science Foundation.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.