Strongly-Coupled Dusty Plasmas

这个项目是关于强耦合尘埃等离子体中波、输运、非平衡涨落和粘弹性行为的基础实验研究。强耦合等离子体是粒子间势能大于粒子动能的电离气体。它们的行为像晶体或液体，不像人们更熟悉的弱耦合等离子体，后者的行为像气体。尘埃等离子体是由微米大小的固体物质、电子、离子和中性气体组成的四组分混合物。固体粒子由于收集电子和离子而带电。等离子体鞘中的电场可以将这些带电粒子悬浮在重力的作用下，从而限制一维、二维或三维的粒子云。一个粒子的电荷很大，通常Q=-10,000个电子电荷，所以成对的粒子有很大的粒子间排斥力。这种斥力的巨大势能，加上气体阻力使粒子冷却，导致粒子之间的强耦合。通过调整粒子的操纵和限制，实验被用来研究统计力学、输运和非线性波中的各种物理现象。该项目的更广泛影响包括：广泛的物理学科感兴趣的交叉研究主题、外联、对研究生和本科生的培训以及成果的广泛传播。

This project is a fundamental experimental study of waves, transport, nonequilibrium fluctuations, and viscoelastic behavior in strongly coupled dusty plasmas. Strongly coupled plasmas are ionized gases in which the interparticle potential energy is greater than the particle kinetic energy. They behave like a crystal or liquid, unlike the more familiar weakly coupled plasmas, which behave like a gas. A dusty plasma is a four-component mixture of micron-size particles of solid matter, electrons, ions, and neutral gas. The solid particles become charged due to collecting electrons and ions. The electric field in a plasma sheath can levitate these charged particles against gravity, allowing the confinement of 1D, 2D or 3D clouds of particles. A particle's charge is large, typically Q = -10,000 electronic charges, so that pairs of particles have a large interparticle repulsion. The large potential energy of this repulsion, together with a cooling of particles by gas drag, lead to strong coupling among the particles. By tailoring the manipulation and confinement of the particles, experiments are performed to study a variety of physical phenomena in statistical mechanics, transport and nonlinear waves. The broader impact of this project includes: cross-cutting research topics of interest to a wide range of physics disciplines, outreach, training of graduate and undergraduate students, and broad dissemination of results.