Diagnostics and Evolution of the Non-Linear Richtmyer-Meshkov Instability

We study analytically and numerically the evolution of the two-dimensional coherent structure of bubbles and spikes in the Richtmyer-Meshkov instability (RMI) for fluids with a finite density ratio. New diagnostics and scalings are suggested for accurate quantification of RMI dynamics. New similarity features of the late-time instability evolution are observed. The results obtained can serve as benchmarks for high energy density laboratory experiments.