论文标题
一维冷气中的飞溅
A splash in a one-dimensional cold gas
论文作者
论文摘要
我们考虑一组硬点粒子在正半线上均匀分布，最初在静止状态下分布着指定的密度。粒子质量在两个值之间交替，$ m $和$ m $。颗粒通过节省能量和动量的碰撞相互作用。我们研究了当左最多粒子的正速度时产生的一系列活动。长期以来，我们发现这导致了观察到的动力学中的两个引人入胜的特征。首先，在大部分气体中，冲击锋会形成将冷气与热区域分开的。冲击前的滑动行进是从欧拉流体动力学的自相似溶液描述的。其次，是由后退颗粒形成的飞溅区域，该区域以负速度向弹道移动。飞溅区是完全非流动力学的，我们提出了两种猜想，用于该区域长期粒子动力学。我们对这些共存制度提供了详细的分析理解。这些由分子动力学模拟的结果支持。
We consider a set of hard point particles distributed uniformly with a specified density on the positive half-line and all initially at rest. The particle masses alternate between two values, $m$ and $M$. The particles interact via collisions that conserve energy and momentum. We study the cascade of activity that results when the left-most particle is given a positive velocity. At long times we find that this leads to two fascinating features in the observed dynamics. First, in the bulk of the gas, a shock front develops separating the cold gas from a thermalized region. The shock-front travels sub-ballistically, with the bulk described by self-similar solutions of Euler hydrodynamics. Second, there is a splash region formed by the recoiled particles which move ballistically with negative velocities. The splash region is completely non-hydrodynamic and we propose two conjectures for the long time particle dynamics in this region. We provide a detailed analytic understanding of these coexisting regimes. These are supported by the results of molecular dynamics simulations.
