A Universal Equation of State for Fluids and Solids at Shock Pressures

Abstract

The present paper is a summary review of the authors’ work on a universal reduced variables formulation of the thermodynamics of very high pressures. It is important to mention that one of the most interesting results of this formalism is an explicit analytic form of the equation of State for shock-compressed matter; this equation seems to be universal in the sense that it is valid for any material and independent of the initial phase. Our earliest papers on this subject were published about seven years ago [1,2] but the main results obtained during the last three years include a law of corresponding states [3], an equation of State for solids [4–6], and an extension of this equation of State to fluids [7,8]. This chronological approach will not be followed here. Instead, only the most important results as well as those unanswered questions and unresolved problems encountered within the formalism will be mentioned. This Situation is a consequence of the manner in which the formalism was developed. The main task was first to look for an equation of State of solids; when this equation was obtained, there were already some unresolved problems, but it was necessary to test the universal validity of the equation. Afterwards, efforts were concentrated in extending the validity of the equation to liquids and gases; the number of unresolved problems increased accordingly.