Study on magnetized strongly coupled plasmas by using charged fine particles in a liquid

通过将带电微粒限制在油表面，建立了一个简单的二维强耦合单组分等离子体系统。将细小的二氧化硅（SiO_2）颗粒置于硅油填充的凹电极底部，通过对涂有导电膜（ITO）的上部玻璃电极施加电压而充电。微粒在电极间的电场作用下向上运动，在表面张力作用下被限制在油表面。该体系与胶体悬浮液相比，在研究二维库仑凝固过程中具有以下优点：易于通过电压控制颗粒的电荷，可减少绝缘油中屏蔽库仑电位的杂质离子数量。我们观察到了库仑晶体生长的长时间演化过程以及晶体中缺陷和位错的发展。我们还利用Ni包覆的细颗粒研究了粒子间磁偶极相互作用的影响。

A simple two-dimensional (2-D) strongly coupled one-component plasma system has been developed by confining charged fine particles on oil surface.The fine silica (SiO_2 particles placed on the bottom of concave electrode where silicon oil is filed are charged up by applying a voltage with respect to the upper glass electrode which is coated by electro-conductive film (ITO). The particles move upward by the electric field between the electrodes and confined on the oil surface by the surface tension.This new system has several advantages in studying 2-D Coulomb solidification compared with the colloidal suspension in a water: the charge of the particles can be easily controlled by the voltage, the number of impurity ions which shield out the Coulomb potential can be reduced in the insulating oil.We observed the long time evolution of Coulomb crystal growth and the development of defect and dislocation in the crystal. We also study the effect of magnetic dipole interactions among particles by using Ni coated fine particles.