Thermodynamic instability and critical fluctuations in dusty plasmas modelled as Yukawa OCP

The Helmholtz free energy of dusty plasmas is analysed as a one-component Yukawa system embedded in an ambient background plasma, and thermodynamic quantities are given in the form of simple interpolation formulae applicable in the domain of intermediate and strong coupling. By calculating the spectrum of the long wavelength fluctuations of the ambient plasma density, it is shown that there is a possibility of observing the divergence in the isothermal compressibility of the Yukawa OCP (a thermodynamic instability of a homogeneous phase) as an enhancement of fluctuation amplitudes and the critical condition is given as a combination of parameters for dusty plasmas.