Nersisyan H B, Osipyan D A, Zwicknagel G
Division of Theoretical Physics, Institute of Radiophysics and Electronics, Alikhanian Brothers Street 1, 378410 Ashtarak, Armenia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 May;77(5 Pt 2):056409. doi: 10.1103/PhysRevE.77.056409. Epub 2008 May 30.
The electric microfield distribution (MFD) at a neutral point is studied for two-component (TCP) electron-ion plasmas using molecular-dynamics simulation and theoretical models. The particles are treated within classical statistical mechanics using an electron-ion Coulomb potential regularized at distances less than the de Broglie length to take into account quantum-diffraction effects. Corrections to the potential-of-mean-force exponential (PMFEX) approximation recently proposed for the MFD at an impurity ion in a strongly coupled TCP [Nersisyan, Phys. Rev. E 72, 036403 (2005)] are obtained and discussed. This has been done by a generalization of the standard Baranger-Mozer and renormalized cluster expansion techniques originally developed for the one-component plasmas to the TCPs. The results from this theoretical model are compared with those from molecular-dynamics simulations. In particular, for a strongly coupled TCP with an ionic charge Z>5 the agreement with numerical simulations is excellent. For still increasing coupling we furthermore found that the PMFEX scheme becomes insufficient to predict the MFD at a neutral point, while its improved version quite well agrees with the simulations.
利用分子动力学模拟和理论模型，对双组分（TCP）电子 - 离子等离子体中性点处的电微场分布（MFD）进行了研究。在经典统计力学框架内，使用在小于德布罗意长度的距离处正则化的电子 - 离子库仑势来处理粒子，以考虑量子衍射效应。针对强耦合TCP中杂质离子处MFD最近提出的平均力势指数（PMFEX）近似的修正被得到并进行了讨论。这是通过将最初为单组分等离子体开发的标准巴兰热 - 莫泽和重整化团簇展开技术推广到TCP来实现的。将该理论模型的结果与分子动力学模拟的结果进行了比较。特别是，对于离子电荷Z>5的强耦合TCP，与数值模拟的一致性非常好。对于进一步增加的耦合，我们还发现PMFEX方案不足以预测中性点处的MFD，而其改进版本与模拟结果相当吻合。
