Abstract
Thermodynamics of fine particle plasmas, systems composed of micron-sized fine particles, ions, and electrons, has been analyzed in the domain where fine particles are strongly interacting with eachn other. It is shown that we may possibly observe a divergence in the isothermal compressibility of the system when the coupling becomes sufficiently strong in the microgravity environment. This is regarded as a manifestation of the tendency of the one-component plasma (OCP) that it becomes thermodynamically unstable with the increase of coupling. This property is closely related to the definition of the OCP where the neutralizing background has no contribution to the pressure and is usually difficult to observe being suppressed by the rigidity of the background of real materials. In the case of fine particle plasmas, however, the background composed of ions and electrons is not completely rigid and extremely strong coupling between fine particles leads to a diverging isothermal compressibility of the whole system. In order to have a bulk three-dimensional system including fine particles with macroscopic masses, we have to perform experiments under the condition of microgravity. The phase diagrams including related phase separation and the critical point are shown and pointed out is a possibility to have a critical point in the solid phase.
