Experimental determination of the conditions for the transition of Jupiter’s atmosphere to the conducting state

The intensity of optical radiation and resistance of a hydrogen-helium layer with He mass fraction Y=m _He/(m _He+m _H)≅0.24, which corresponds to the composition of the outer layers of Jupiter’s atmosphere [2], were simultaneously measured under multiple shock compression up to 164 GPa in plane geometry. The initial pressure and temperature of the mixture were equal to 8 MPa and 77.4 K, respectively, and the velocity of steel strikers was equal to 6.2 km/s. These conditions allowed the generation of the final compressed curve close to the adiabatic states of Jupiter’s atmosphere according to the models proposed in [2, 3]. The conditions for the appearance of the conducting phase in the compression process and the achieved level of electrical conductivity were determined. The experimental data were compared with the one-dimensional fluid-dynamic simulation of the compression process using the equation of state for the mixture in a model similar to the one proposed in [3, 8]. The experimental data were also compared with the behavior of pure components having the same initial density as in the mixture and compressed to the same final pressure.