Stimulated Brillouin scattering in shock-compressed fluids

We have demonstrated that stimulated Brillouin scattering can be used to measure the velocity of sound in shock‐compressed fluids with 1% precision. We have constructed a ruby laser which can be triggered by a Pockels cell as the shock wave reaches a predetermined point in the sample. The primary limit of accuracy is the lack of precise data for the refractive index at higher pressure. We have also measured the shock velocity U _s in terms of the material velocity U _p. The data have been fitted to the relation $U_s{\text{=1.4932+1.9615U}}_p{\text{+0.0750U}}_p^2\hspace{0.17em}\mathrm{km}/\sec$ for water below 15‐kbar shock stress.