CAREER: Transport Phenomena in Ultracold Neutral Plasmas

该学院早期职业发展(CALEAR)计划奖支持对超冷中性等离子体输运性质的基础理论研究。超冷等离子体是一种新的物质状态，因为低温导致组成粒子--电子和离子--强烈耦合。这种介质具有与传统等离子体完全不同的性质，类似于液体与气体的不同之处。强耦合等离子体出现在影响能源、安全和基础物理研究的几个学科中。例如，在惯性约束聚变实验中发现的高密度等离子体，强烈的激光-材料相互作用研究，声致发光微泡，以及诸如白矮星和巨行星内部的天体物理对象。超冷等离子体为观察这一物理现象提供了一个独特的窗口，因为它们可以用激光精确测量。这使得能够对理论模型进行详细的测试。除了理论研究外，还有一个免费的外展项目，将通过一个名为“什么是等离子体”的互动演示向公众介绍等离子体物理学。这将是爱荷华大学(UI)空间科学史大型展览的组成部分，该展览将由爱荷华大学自然历史博物馆展出，随后将作为巡回展览在爱荷华大学移动博物馆展出。超冷等离子体是由激光诱导捕获的超冷原子电离形成的，产生冷离子和电子的电荷中性混合物。该项目提供的进展是统计力学理论和分子动力学模拟，能够解释等离子体的两个组成部分。在这个相对较新的领域，理论和模拟都集中在单组分模型上，将等离子体视为单一流体。新的进展解决了双组分物理问题，随着实验努力降低温度，这一问题将变得越来越重要。将强调的特殊过程是状态方程、互扩散、粘度和能量松弛速率。该项目将专注于了解各种微观物理过程如何影响宏观输运，包括电子和离子电荷的相反符号，电子和离子的非平衡性质，以及等离子体的动态介电响应。这些结果将为强耦合等离子体的基础物理提供见解，为几个前沿研究领域做出贡献。

This Faculty Early Career Development (CAREER) Program award supports a fundamental theoretical investigation of the transport properties of ultracold neutral plasmas. Ultracold plasmas are a novel state of matter because the low temperature causes constituent particles, electrons and ions, to be strongly coupled. This medium has fundamentally different properties than traditional plasmas, analogous to the ways in which liquids differ from gases. Strongly coupled plasmas arise in several disciplines influencing energy, security and fundamental physics research. Examples include dense plasmas found in inertial confinement fusion experiments, intense laser-material interaction studies, sonoluminescing microbubbles, as well as astrophysical objects such as white dwarfs and giant planet interiors. Ultracold plasmas provide a unique window to view this physics because they can be accurately measured using lasers. This enables detailed tests of theoretical models. In addition to the theoretical research, a complimentary outreach program will introduce the public to plasma physics through an interactive "What is Plasma" demonstration. This will be an integral part of a larger exhibit on the history of space science at the University of Iowa (UI) to be displayed by the UI Natural History Museum, and later as a traveling exhibit in the UI Mobile Museum. Ultracold plasmas are formed by laser-induced ionization of trapped ultracold atoms, resulting in a charge-neutral mixture of cold ions and electrons. Advances provided by this project are statistical mechanical theory and molecular dynamics simulations capable of accounting for both components of the plasma. Theory and simulations in this relatively new field have focused on one-component models, treating the plasma as a single fluid. The new advances address two-component physics that will become increasingly important as experiments strive for lower temperatures. The particular processes that will be emphasized are equation of state, mutual diffusion, viscosity and energy relaxation rates. The project will focus on understanding how various microphysics processes affect macroscopic transport, including the opposite sign of electron and ion charge, the nonequilibrium nature of electrons and ions, and the dynamic dielectric response of the plasma. The results will provide insights into the fundamental physics of strongly coupled plasmas, contributing to several frontier research fields.