We report the highest compression reached in laboratory plasmas using eight laser beams, E laser ≈12 kJ, τ laser =2 ns in third harmonic on a CD 2 target at the ShenGuang-II Upgrade (SGII-Up) facility in Shanghai, China. We estimate the deuterium density ρ D = 2.0 ± 0.9 kg/cm 3 , and the average kinetic energy of the plasma ions less than 1 keV. The highest reached areal density Λρ D =4.8 ± 1.5 g/cm 2 was obtained from the measured ratio of the sequential ternary fusion reactions (dd→t+p and t+d→α+n) and the two body reaction fusions (dd→ 3 He+n). At such high densities, sequential ternary and also quaternary nuclear reactions become important as well (i.e. n(14.1 MeV) + 12 C → n'+ 12 C* etc.) resulting in a shift of the neutron (and proton) kinetic energies from their birth values. The Down Scatter Ratio (DSR-quaternary nuclear reactions) method, i.e. the ratio of the 10-12MeV neutrons divided by the total number of 14.1MeV neutrons produced, confirms the high densities reported above. The estimated lifetime of the highly compressed plasma is 52 ± 9 ps, much smaller than the lasers pulse duration.

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