  Compression wave analysis started nearly 50 years ago with Fowles.[1]
Coperthwaite and Williams [2] gave a method that helps identify simple and
steady waves. We have been developing a method that gives describes the
non-isentropic character of compression waves, in general.[3] One result of
that work is a simple analysis tool. Our method helps clearly identify when a
compression wave is a simple wave, a steady wave (shock), and when the
compression wave is in transition. This affects the analysis of compression
wave experiments and the resulting extraction of the high-pressure equation of
state.
