Onset of Turbulence in Dusty Plasma Liquids

这个项目将通过数值模拟尘埃粒子在等离子体环境中的运动，来研究引导带电介质中湍流开始的基本物理机制。带电介质是由电子、离子和尘埃粒子组成的等离子体。理解带电介质中从层流到湍流的转变是非常重要的科学挑战之一，因为它影响到复杂的过程，如核聚变、大气中化学品的扩散、大气风暴的形成和飞机的稳定性。例如，飞行湍流很常见，但这种现象的产生可能受到各种因素的影响，包括风流、压力或温度梯度，以及尘埃大气中的自感电力，包括闪电。在等离子体条件下，尘埃颗粒带电并形成尘埃等离子体液体，在那里可以观察到各种波动和不稳定性。这使得尘埃等离子体成为研究从层流到湍流转变的理想模型系统。尘埃等离子体的动力学受尘埃-尘埃相互作用和尘埃与等离子体的相互作用所指导，这两者都会导致尘埃的反常扩散。在这个项目中，研究小组将调查异常扩散与全球不稳定的开始之间的联系，例如湍流。研究小组将开发一种内部分析代码，利用光谱理论和分数阶微积分中的新数学技术来模拟具有非局部相互作用的无序介质中的异常粒子扩散。对于给定的扩散行为，分析程序将根据系统能谱的演化确定相应的随时间演化的动力学状态。为了验证这项新技术，光谱分析的预测将与分子动力学模拟的结果以及使用表现出湍流行为的尘埃等离子体液体的实验结果进行比较。这一奖项反映了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 project will investigate the fundamental physical mechanisms guiding onset of turbulence in charged media, a plasma composed of electrons, ions, and dust particles, by numerically modeling the motion of dust particles in the plasma environment. Understanding the transition from laminar to turbulent flow in charged media is one of the very important scientific challenges as it affects complex processes such as nuclear fusion, dispersion of chemicals in the atmosphere, formation of atmospheric storms, and aircraft stability. For example, flight turbulence is common, yet the origin of such phenomenon can be affected by a variety of factors, including wind flows, pressure or temperature gradients, and self-induced electricity, including lightning, in dusty atmospheres. In plasma conditions, the dust particles become charged and can form dusty plasma liquids, where various waves and instabilities can be observed. This makes dusty plasmas an ideal model system for the study of the laminar-to-turbulent transition.The dynamics of dusty plasmas is guided by the dust-dust interaction and the dust interaction with the plasma, both of which can lead to anomalous dust diffusion. In this project, the research team will investigate the connection between anomalous diffusion and the onset of a global instability, such as turbulence. The research team will develop an in-house analysis code, employing novel mathematical techniques from spectral theory and fractional calculus to model anomalous particle diffusion in disordered media with non-local interactions. For a given diffusion behavior, the analysis code will determine the corresponding time-evolved dynamical state of the system based on the evolution of its energy spectrum. To verify this novel technique, the predictions from the spectral analysis will be compared against the results from molecular dynamics simulations as well as experiments employing dusty plasma liquids exhibiting turbulent behavior.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.