Analysis of the particle interactions in a two-dimensional-plasma dust crystal and the use of dust as a probe of the time-averaged presheath electric field.
Analysis of the particle interactions in a two-dimensional-plasma dust crystal and the use of dust as a probe of the time-averaged presheath electric field.
复制标题
分析二维等离子体尘埃晶体中的粒子相互作用以及使用尘埃作为时间平均预鞘电场的探针。
DOI：
10.1103/physreve.66.046407
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
K. E. Greenberg
中科院分区：
文献类型：
--
作者：
G. Hebner;Merle E. Riley;K. E. Greenberg
提出了一种测量等离子体中二维(2D)层内尘埃粒子相互作用的方法，并使用尘埃作为探针来确定等离子体预生电场。粒子间的相互作用是由抛物线势垒中二维等离子体尘埃晶体的横向压缩直接确定的。通过观察单粒子落入势井内的轨迹，确定了抛物线势井的形状。粒子轨迹与利用激光诱导荧光测量Ar亚稳态速度分布得出的气体温度计算的值非常一致，并假设气体扩散散射。测量的粒子分离与晶体的状态方程相结合，得出了等离子体屏蔽长度和粒子上的电荷的值。在一定的等离子体功率、压力和颗粒直径(质量)范围内测量了筛分长度和电荷。通过对粒子高度和电荷的分析，得到了射频驱动等离子体鞘边缘的时间平均电场。测量的电场范围为5~22V/cm。对于较小的颗粒直径，离子风力与重力相当。这些测量表明，粒子被限制在经典玻姆点的体等离子体一侧。
A method for measuring the interactions of dust particles within a two-dimensional (2D) layer in a plasma is presented, along with the use of dust as a probe for determining plasma presheath electric fields. Particle interactions were directly determined from the lateral compression of two-dimensional plasma dust crystals confined in a parabolic potential well. The shape of the parabolic potential well was confirmed by observing trajectories of single particles falling within the well. Particle trajectories were in good agreement with values calculated using gas temperatures derived from laser-induced-fluorescence measurements of the argon metastable velocity distributions and assuming diffusive gas scattering. Measured particle separations combined with an equation of state for the crystal were used to derive values for the plasma screening length and the charge on the particles. Screening lengths and charges were measured for a range of plasma power, pressure, and particle diameter (mass). Analysis of the particle heights and charge were used to derive the time-averaged electric fields at the edge of the rf driven plasma sheath. Measured electric fields were between 5 and 22 V/cm. For smaller particle diameters, the ion wind force was comparable to the force of gravity. These measurements showed that the particles are confined to the bulk-plasma side of the classical Bohm point.