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 [lt]0. The growth of imposed interfacial perturbations [eta]=[eta][sub 0] sin[ital kx] agrees with linear theory if the pre- and postshock initial amplitudes are averaged. When [ital k][eta][similar to]2, the fundamental mode saturates and harmonics emerge producing a slowly developing bubble and spike.