抄録
In dusty plasmas, dust particles are negatively charged and massive so as to be affected by gravity. In microgravity experiments with a cylindrical discharge, the dust particles move their equilibrium position with changing their arrangements from an isotropic closed-packed structure to anisotropic linear chains. The Coulomb potential dominant in the isotropic structure was evaluated based on mesurement of plasma parameters of ion density and electron temperature. It was found that the Coulomb coupling parameters of the ratio of the potential to thermal energy were large enough to solidify Coulomb crystals of the dust particles. Neverthless the Coulomb potential can not overcome the potential forming the linear chains which appares in a microgravity condition, so-called wake potential induced by ion stream along the axis of the cylindrical discharge.
