Richtmyer-Meshkov experiments on the Nova laser at high compression

We investigate the shock induced Richtmyer-Meshkov instability at high compression using the Nova laser. The instability and shock characteristics are measured radiographically in planar two-fluid targets with Atwood number <0. The growth of imposed interfacial perturbations η=${\mathrm{\eta }}_0$ sinkx agrees with linear theory if the pre- and postshock initial amplitudes are averaged. When kη∼2, the fundamental mode saturates and harmonics emerge producing a slowly developing bubble and spike.