标题： 非均匀强耦合尘埃等离子体中的偶极传播：黏弹性流体方法 显示英文标题

标题： Dipole Propagation in Inhomogeneous Strongly Coupled Dusty Plasmas: A Viscoelastic Fluid Approach

摘要： 流体涡旋，特别是单极子和偶极子，在均匀粘弹性流体中的传播特性在最近的一篇出版物[Phys. Plasmas 23, 013707 (2016)]中有所报道。 在那项研究中，尘埃等离子体被建模为粘弹性流体，使用广义流体动力学模型的不可压缩极限，在强耦合条件下模拟，此时系统保持流体状态但表现出显著的粒子间相关性，势能远超动能。 本文中，我们通过采用相同的模型来研究由两个反向旋转的Lamb-Oseen涡旋表示的偶极子在非均匀介质中的演化。研究表明，偶极子的整体动力学由横向剪切波强度与偶极子结构中涡旋的环流强度之间的竞争决定，前者与粘弹性背景介质的弹性强度成正比。 通过平滑和尖锐截止方式沿垂直于偶极子运动方向的竖直方向引入密度非均匀性。 数值模拟显示，偶极子的较高环流强度或背景介质的较低耦合强度使得偶极子能够存活更长时间，并沿着更明显的弯曲轨迹向高密度侧移动。 虽然环流强度和耦合强度在两种密度下的总体效应相似，但在平滑密度情况下，涡旋周围的界面逐渐形成蘑菇状结构；而在尖锐情况下，则形成简单的螺旋包络。 这些效应通过基于不可压缩广义流体动力学模型的二维模拟可视化展示。 显示英文摘要

摘要： The propagation characteristics of fluid vortices, particularly monopoles and dipoles, in a homogeneous viscoelastic fluid were reported in a recent publication [ Phys. Plasmas 23, 013707 (2016)]. In that study, a dusty plasma was modeled as a viscoelastic fluid using the incompressible limit of the generalized hydrodynamic model under strongly coupled conditions in a regime where the system remains in a fluid state but exhibits significant interparticle correlations, with potential energy dominating over kinetic energy. In this paper, we extend the previous work by employing the same model to investigate the evolution of a dipole represented by two counter rotating Lamb-Oseen vortices in an inhomogeneous medium. It is shown that the entire dynamics of a dipole is governed by the competition between the strength of transverse shear waves, which is proportional to the elastic strength of the viscoelastic background medium, and the circulation strength of the vortices in the dipole structure. The density inhomogeneity is introduced along the vertical direction, perpendicular to the direction of dipole motion, using both smooth and sharp cutoffs. The numerical simulations show that a higher circulation strength of a dipole or lower coupling strength of the background medium allows the dipole to survive longer and follow a more pronounced curved trajectory toward the high-density side. While the overall effects of circulation and coupling strength are similar in both densities, the resulting structure morphologies differ in the smooth density case, the interface around the vortices gradually forms a mushroom-like shape, whereas in the sharp case, it forms a simple spiral envelope. These effects are visualized through two dimensional simulations based on the incompressible generalized hydrodynamic model.