Schmidt Christian, Piel Alexander
IEAP, Christian-Albrecht-Universität, D-24098 Kiel, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Oct;92(4):043106. doi: 10.1103/PhysRevE.92.043106. Epub 2015 Oct 19.
The Brownian motion of a single particle in the plasma sheath is studied to separate the effect of stochastic heating by charge fluctuations from heating by collective effects. By measuring the particle velocities in the ballistic regime and by carefully determining the particle mass from the Epstein drag it is shown that for a pressure of 10 Pa, which is typical of many experiments, the proper kinetic temperature of the Brownian particle remains close to the gas temperature and rises only slightly with particle size. This weak effect is confirmed by a detailed model for charging and charge fluctuations in the sheath. A substantial temperature rise is found for decreasing pressure, which approximately shows the expected scaling with p(-2). The system under study is an example for non-equilibrium Brownian motion under the influence of white noise without corresponding dissipation.
研究了单个粒子在等离子体鞘层中的布朗运动，以区分电荷涨落引起的随机加热效应与集体效应引起的加热效应。通过测量弹道 regime 中的粒子速度，并通过 Epstein 阻力仔细确定粒子质量，结果表明，对于许多实验中典型的 10 Pa 压力，布朗粒子的适当动力学温度保持接近气体温度，并且仅随粒子尺寸略有升高。鞘层中充电和电荷涨落的详细模型证实了这种微弱效应。发现随着压力降低，温度有显著升高，大致呈现出预期的 p(-2) 比例关系。所研究的系统是在白噪声影响下无相应耗散的非平衡布朗运动的一个例子。
