Structure changes of Coulomb crystal in a carbon fine-particle plasma

The changes of particle arrangement in a methane/helium plasma during particle growth have been observed and quantitatively analyzed using the Monte-Carlo simulation. It has been suggested that a 3-dimensional Coulomb crystal changes to the liquid phase with the growth due to a change in the direction of force. It has been found that the liquid changes to a 2-dimensional crystal as a result of an increase in particle charge. A force due to polarization of negatively charged particles and the surrounding positive ions in the direction perpendicular to electrodes, as well as an isotropic Coulomb force, plays an important role in the formation of Coulomb crystals.