Introduction to Streaming Complex Plasmas A: Attraction of Like-Charged Particles

Abstract

Like-charged particles usually interact via a repulsive force. However, in streaming dusty plasmas one can observe that two negatively charged dust particles may attract each other. This is explained by accumulation of positive ions below the dust particles (with respect to the streaming direction). In this chapter, we describe the dependence of this ion focus and the resulting wakes on discharge rf-power, pressure and thermophoretic force, as the three key parameters, that can be varied in dusty plasma experiments. Moreover, we discuss the impact of this attractive force on the collective properties of many dust particles, in particular, on the structure and on the dynamics of spherically confined clusters.