物理学报2016，Vol.65Issue(6)：225-232,8.DOI:10.7498/aps.65.065201
温稠密钛电导率计算
A simple and effective simulation for electrical conductivity of warm dense titanium
摘要
Abstract
A linear mixture rule has been used to calculate the electrical conductivity of warm dense titanium plasmas in the density and temperature ranges of 10−5–10 g·cm−3 and 104–3 × 104 K, in which the interactions among electrons, atoms, and ions are considered systemically. In the first place, the coupling and degeneracy parameters of titanium plasma are shown as a function of density and temperature in the warm dense range. The warm dense titanium plasmas span from weakly coupled, nondegenerate region to strongly coupled, degenerate domain in the whole density and temperature regime. The titanium plasma becomes strongly coupled plasma at higher than 0.22 g·cm−3 and almost in the whole temperature range where the coupling parameter Γii > 1. In particular, the Coulomb interactions become stronger at higher than 0.56 g cm−3 where 10<Γii <216. At the same time, the titanium plasma is in the degenerate regime at higher than 0.35 g·cm−3 where the degeneracy parameterΘ<1, and is in the nondegenerate or partial degenerate regime at lower than 0.35 g·cm−3 where Θ > 1. The influence of temperature on the coupling and degeneracy parameters is less than that of the density, and the plasma composition is calculated by the nonideal Saha equation felicitously. Thus the ionization degree decreases with increasing density at lower density, which is due to the thermal ionization in that regime where the free electrons have sufficiently high thermal energy. Meanwhile, the ionization degree increases with the increase of density at higher than 0.1 g·cm−3, in which the pressure ionization takes place in the region where the electrons have sufficiently high density and the collisions increase rapidly. There is a minimum for the ionization degree at about 0.1 g·cm−3, while the maximum ionization degree reaches 4 at 10 g·cm−3. In the whole temperature regime, the titanium plasma is mostly in the partial plasma domain at lower than 1 g·cm−3, and becomes completely ionized at higher than 1 g·cm−3. The calculated conductivity is in reasonable agreement with the experimental data. At a fixed temperature, there is a minimum in each of the ionization curves at lower than 3 × 104 K. And the position of the minimum is shifted towards decreasing density with increasing temperature. The conductivity monotonously increases as the density increases at a temprature of 3 × 104 K. At a constant density, the conductivity increases with increasing temperature for lower than 0.56 g·cm−3, while it decreases with increasing temperature for higher than 0.56 g·cm−3. This behavior is connected with the nonmetal to metal transition in a dense plasma regime. So the nonmetal to metal transition indense titanium plasma occurs at about 0.56 g·cm−3 and its corresponding electrical conductivity is 1.5 × 105 Ω−1·m−1. Finally, the contour of electrical conductivity of titanium plasma is shown as a function of density and temperature in the whole range. Its electrical conductivity spans a range from 103 to 106 Ω−1·m−1. It can be seen that the titanium plasma gradually approaches the semiconducting regime as temperature increases. When the order of magnitude of the electrical conductivity reaches 105 Ω−1·m−1, the plasma almost becomes conducting fluid in the higher density range. This also demonstrates that a nonmetal-metal transition has taken place in the warm dense titanium plasma.关键词
温稠密钛/线性混合规则/电导率Key words
warm dense titanium/linear mixture rule/electrical conductivity引用本文复制引用
付志坚,贾丽君,夏继宏,唐可,李召红,权伟龙,陈其峰..温稠密钛电导率计算[J].物理学报,2016,65(6):225-232,8.基金项目
国家自然科学基金(批准号:11074266,11071025)、中国工程物理研究院科技发展基金(批准号:2013 A0101001)、中国工程物理研究院冲击波物理和爆轰物理国家重点实验室基金(批准号:9140 C670103150 C67289)、重庆市教育委员会科学技术研究项目(批准号：KJ131222, KJ121209)、中国博士后科学基金(批准号:2015 M572497)和重庆文理学院项目(批准号：R2012DQ05)资助的课题.* Project supported by the National Natural Science Foundation of China (Grant Nos.11074266,11071025), the Scientific Research Fund of Chongqing Municipal Education Commission of China (Grant Nos. KJ131222, KJ121209), the Science and Technology Development Foundation of China Academy of Engineering Physics (Grant No.2013 A0101001), the Foundation of Laboratory of Shock Wave and Detonation Physics, CAEP (Grant No.9140 C670103150 C67289), the China Postdoctoral Science Foundation (Grant No.2015 M572497), and the Chongqing University of Arts and Sciences Foundation, China (Grant No. R2012DQ05) （批准号:11074266,11071025）
