The authors in the paper below did a simulation of plasma plume evolution from a laser heated metal target. They used compressible transport equations and ideal gas EOS for Ar.
I am having difficulty understanding their initial condition. They say ", the initial internal pressure of plasma is assumed constant, 210 MPa.". How is this value determined or assumed. It is based on the temperature of the surface?
So, im thinking about the problem some more, and it seems the density is what should be known because when ablation occurs, phase transition occurs in the metal surface which generates a vapor.
S. Harilal, G. V. Miloshevsky, P. K. Diwakar, N. L. LaHaye, and A. Hassanein, Phys. Plasmas 19(8), 083504 (2012).