Shock compression of liquid deuterium up to $109\mathrm{GPa}$

Hugoniot points of liquid ${\mathrm{D}}_2$ were measured at shock pressures of 107, 54, and $28\mathrm{GPa}$ using converging explosively driven systems (CSs). The two data sets measured with a laser $\left(L\right)$ and pulsed currents (PCs) differ substantially. Our results are in excellent agreement with the PC data and the error bars of the CS-PC data are less than half those of the $L$ data. The limiting compression obtained from the best fit to the CS-PC data is $4.30\pm 0.10$ at $100\mathrm{GPa}$. The CS-PC data are in good agreement with path integral Monte Carlo and density functional theory calculations, which is expected to be the case at even higher shock temperatures and pressures, as well.

Figure 1

Shock velocity $u_s$ versus mass velocity $u_p$ for deuterium: open diamonds (this work), open triangles (Refs. 7, 8), solid squares (Refs. 2, 3, 4), solid circles (Ref. 9), open squares (Ref. 1). Solid curve is least-squares fits in regions 1–3; dashed curve in region 4 is linear fit to Ref. 1.

Figure 2

Pressure $\left(P\right)$ versus compression $(\rho ∕{\rho }_0)$ calculated with Hugoniot equations and $u_s\text{−}{u}_p$ fits in Fig. 1. Solid and dashed curves correspond to solid and dashed curves in Fig. 1. Error bars are standard deviations of fits calculated from uncertainties in measured shock velocities. Dotted curve and temperatures were calculated with PIMC (Ref. 22). Open circles calculated with DFT (Ref. 23).

Figure 3

$d{u}_s∕d{u}_p$ versus $u_p$. Solid curve: 1 is from Ref. 9; 2 is derivative of solid curve in Fig. 1 for $9<u_p<17\mathrm{km}∕\mathrm{s}$; 3 is linear slope of solid line above $u_p=15\mathrm{km}∕\mathrm{s}$ in Fig. 1. Dissociation occurs between $u_p=\sim 9$ and $\sim 15\mathrm{km}∕\mathrm{s}$, which corresponds to 20 and $50\mathrm{GPa}$ (Ref. 20). Dashed line is slope of dashed line in region 4 of Fig. 1. Error bars are standard deviations of slopes $S$ of linear fits caused by uncertainties in shock velocity measurements. Dot-dash lines are slopes corresponding to limiting compressions of monatomic and diatomic ideal gases and free-electron gas, as indicated.