尘埃颗粒充电及大小分布对等离子体输运及波动现象的影响

By considering the charging and size distribution of dust grains, we study the dusty plasma and try to obtain the dispersion relation, the character of dust acoustic wave, dust ion acoustic wave, dust negative ion wave, shock wave and the transport coefficient..We will deduce the formulation of conductivity for the dust plasma at weak ionization considering the dust size distribution and charging of the dust grains, by solving the Boltzmann' equation and Shukla equation, which are the governing equations on dust grain charge and discharge processes, provided that the weak external electromagnetic field is imposed.By considering the size distribution and charging of the dust grains, we also consider a dusty multi-ion plasma system containing electrons, light positive ions, heavy negative ions, a extremely massive (few micron size) charge fluctuating dust grains. The dust negative ion acoustic (DNIA) shock waves, which are associated with negative ion dynamics and dust charge fluctuation, will be investigated by employing the reductive perturbation method and the numerical simulation.. Since the characters of the dispersion relation, the parameters of the waves and the transport coefficient can be easily measured in the experiments, we then can obtain some parameter which are difficult to be measured in the experiments such as: the dust size distribution, dust charge, etc. In a conclusion, this project has a potential importance both in theoretical and experimental investigation of the plasma physics.

在普通等离子体中存在尘埃颗粒的等离子体叫尘埃等离子体。等离子体中尘埃颗粒的存在会大大改变等离子体的性质。电磁波在等离子体中传播时，一般等离子体理论由于忽略了尘埃颗粒的作用，结果造成电磁波衰减预期值远小于实际测量值。因此，研究尘埃等离子体中尘埃颗粒的作用具有重要的实际意义与理论意义。.本项目通过考虑尘埃颗粒的充电过程及大小分布分别求解尘埃等离子体流体力学方程组和含碰撞项的带电粒子的Boltzmann 方程。得到不同大小尘埃颗粒的充电过程及大小分布对于等离子体色散关系、多种波的传播特性等物理问题的影响。同时，我们将研究不同大小尘埃颗粒的充电过程对于尘埃等离子体电导、扩散、热传导和粘性的影响。得到输运系数、波的特征参数与尘埃颗粒大小分布、荷电量及充电过程的关系。获得容易测量的物理量和不容易测量的物理量之间的关系。这将对于进一步探索等离子体中尘埃颗粒的作用具有非常重要的理论意义与实际意义。

尘埃颗粒所带的电量是与尘埃颗粒大小有密切而复杂的函数关系。实验指出，无论是在实际的空间坏境中还是在实验室中，尘埃颗粒的形状各不相同。其大小与所带的电量都具有一定的分布范围。本项目不考虑二次电子发射等复杂因素，通过考虑尘埃颗粒的大小分布以及由此引起的尘埃颗粒上所带电量的不同而对尘埃等离子体中尘埃颗粒的集运动行为进行研究。研究多种物理条件下尘埃颗粒大小的分布以及荷电量的不同是如何影响波的色散关系以及孤立波的各种参数等问题。由于色散关系与孤立波的参数包含着尘埃颗粒的许多信息，从而可以通过测量波的色散关系与孤立波的参数来推断尘埃颗粒不易测量的物理参量，例如：可以通过测量波的传播速度振幅等来判断尘埃颗粒所带的电量等一些不易测量的物理量。从而，得到在实验上不易测量的量和容易测量的量之间的关系。为实验提供方法与理论指导。