非平衡等离子体中带电粒子输运特性研究

The knowledge of transport properties is essential for a better understanding of non-equilibrium plasma physics and applications.The purpose of this research is to develop a science-based understanding of charged particle transport properties in non-equilibrium plasmas.Computation of electron transport properties based on multi-term approximation of the Boltzmann equation is improved,including fast estimation of electron temperature Tb which is a free parameter,and comparision of different collision operators,etc.Ion transport properties is obtained with multi-term approximation as well.Then the relaxation processes of electrons is studied under crossed electric and magnetic field.The electron transport properties of mixed gases is discussed.Futhermore the moments of electron velocity distribution function are measured to check the validity of multi-term approximation.Finally a user-friendly software to calculate tranport coefficients is developed.Such investigations will no doubt promote the development of plasma technology.

输运特性是非平衡等离子体物理及应用领域中一个非常重要的问题。我们将针对非平衡等离子体的带电粒子输运特性进行深入研究。完善多项近似法求解玻尔兹曼方程计算电子输运系数，包括自由参数电子温度Tb的快速估计、不同碰撞算子比较等；采用多项近似法计算离子输运系数；研究交叉电磁场作用下等离子体中电子的弛豫过程；计算混合气体的电子输运系数；实验测量速度分布函数的矩，验证算法合理性；开发出界面友好的输运系数计算程序。这些工作将推动等离子体技术的发展。

输运特性是非平衡等离子体及应用领域中一个非常重要的问题。本项目推导了多项近似法求解玻尔兹曼方程的展开系数矩阵方程和电子/离子输运系数表达式，给出了守恒碰撞（弹性和非弹性碰撞）和非守恒碰撞（吸附和电离等）碰撞算子表达式，编写了输运系数计算程序；探讨了自由参数Tb、vmax和lmax对电子输运系数计算精度的影响，研究了吸附和外加磁场对电子输运系数的影响；研究交叉电磁场作用下的电子弛豫特性，发现不同密度等离子体电子弛豫具有相似性；计算了空气、SF6/N2、g3等混合气体的电子输运系数，并与Monte Carlo方法计算结果进行比较；搭建了脉冲汤逊法实验平台，实验测量了电子漂移速度、扩散系数、有效电离系数等参数，验证了计算结果的合理性。这些工作将推动等离子体技术的发展。