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Center for Nonlinear Studies |
Using ab initio molecular dynamics simulations, we calculate the equation of state (EOS) for hydrogen and iron at high pressures. For hydrogen, it has been recently suggested that an ab initio EOS significantly changes the thermonuclear gain of an Inertial Confinement Fusion (ICF) target [Hu et al., PRL 104, 235003 (2010)]. Using this new multi-phase ab initio EOS for hydrogen, we perform a full optimization of the laser pulse shape with hydrodynamic simulations starting from 19 K in DT ice and find, in contrast, that the thermonuclear gain is robust against uncertainties of the EOS. For iron, we calculate the high pressure melting curve to span conditions encountered in the earth inner core (3 Mbar) and for exoplanets up to 10 earth mass (15Mabr). We also investigate the stability of the BCC phase for this entire pressure range. As the melting temperature and solid phase still remain to be measured experimentally at high pressures, we also developed full ab initio calculation of the XANES (X-raynear edge spectroscopy) spectrum. Calculations at normal conditions as well as at high pressure show that XANES measurements could be a useful diagnostics for density, temperature, and phase in dynamics experiments.
Host: T-1