High potential, near free molecular regime Coulombic collisions in aerosols and dusty plasmas
High potential, near free molecular regime Coulombic collisions in aerosols and dusty plasmas
复制标题
高电势、近自由分子状态气溶胶和尘埃等离子体中的库仑碰撞
DOI：
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发表时间：
2019
影响因子：
5.2
通讯作者：
R. Gopalakrishnan
中科院分区：
文献类型：
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作者：
Harjindar Singh Chahl;R. Gopalakrishnan
摘要确定气溶胶和尘埃等离子体中的粒子电荷需要考虑粒子-离子库仑耦合和离子-中性气体分子碰撞的精确计算。虽然任何强度的库仑相互作用的效果在连续极限和自由分子极限中被准确地描述，但在中间碰撞制度下的准确物理描述仍然是难以捉摸的。具体地说，库仑影响相反电荷的粒子和离子之间的碰撞在过去已经逃避了准确的理论描述。我们使用Langevin动力学（LD）的计算来推断作为一个功能的静电势能热能比和扩散Knudsen数的离子中性碰撞指数在有限的压力系统的无量纲碰撞内核。LD的方法产生一个简单的，近似的处理粒子充电在整个离子中性碰撞制度的假设下，其中是离子的质量，是背景气体分子的质量。我们表明，Gumbel分布准确地描述了使用LD计算的基本分布。高离子浓度的影响（在该屏蔽粒子的自由电荷在空间中是重要的）是通过一个无量纲的屏蔽长度参数的分布参数的依赖性分析参数参数化，并导致回归，是有效的和等离子体。当前模型与文献中选定模型的相互比较表明，当前模型和Gatti和Kortshagen（假设）发布的模型对各种气溶胶产生了类似的预测，版权所有© 2019美国气溶胶研究协会
Abstract Determination of the particle charge in aerosols and dusty plasmas requires an accurate calculation of the particle-ion collision kernel taking into account the particle-ion Coulombic coupling and ion-neutral gas molecule collisions. While the effect of Coulombic interactions of any strength is described accurately in the continuum limit and free molecular limit, an accurate physical description at intermediate collisional regimes remains elusive. Specifically, the Coulomb influenced collisions between oppositely charged particles and ions have evaded accurate theoretical description in the past. We use Langevin dynamics (LD) calculations to infer the non-dimensional collision kernel as a function of the electrostatic potential energy to thermal energy ratio and the diffusive Knudsen number the index of ion-neutral collisionality in a finite pressure system. The LD approach yields a simple, approximate treatment of particle charging in the entire ion-neutral collision regime under the assumption that where is the mass of an ion and is the mass of the background gas molecules. We show that the Gumbel distribution accurately describes the underlying distribution of calculated using LD. The effect of high ion concentrations (at which screening of particle by free charges in space is important) on is parameterized through a non-dimensional screening length parameter Analysis of the dependence of the distribution parameters on and leads to a regression for that is valid for and plasmas. Inter-comparison of current model with select models from the literature shows that the current model and the model published by Gatti and Kortshagen (that assumes ) yield similar predictions for a wide range of and Copyright © 2019 American Association for Aerosol Research