Multishock comparison of dense gaseous H2 + He mixtures up to 30 GPa.

Time-resolved spectral radiation histories of the gaseous H(2) + He mixtures under shock loadings were measured by using a six-wavelength channel pyrometer. The initial gaseous mixtures had a mole component of H(2):He = 1:1.21, which were shocked from room temperature and initial pressure of 20 MPa to a pressure range of 1-30 GPa and temperature range of 3000-7000 K by means of a two-stage light-gas gun. Multishock reverberations between the base-plate and sapphire window can be observed up to the fifth-shock compressions. The experimental data are in good agreement with self-consistent fluid variational theory calculations in which the dissociation process of hydrogen molecules and various interactions among atomic and molecular species are taken into account.