Erik Brambrink, LULI Palaiseau
vendredi 16 Octobre 2009 à 10h30 - salle des Séminaires
The earth core is mainly composed of iron, which is partly liquid (outer earth core) and solid (inner earth core). Although seismic studies allow deducing the depth of the liquid-solid boundary, the melting temperature and the contribution of iron solidification the earth core energy balance are still under discussion. The latter one is of special interest, as the convection processes are responsible for the earth magnetic field. Our research program aims to measure the equation of state (EOS) of iron and characterize the melting curve for the relevant parameters (3 Mbar, 6000 K) using high-energy laser systems. As these parameters cannot be reached with shocks, alternative compression techniques, like isentropic compression, are required. The proper characterization of the material properties and melting curve also asks for new x-ray based diagnostics like radiography and diffraction. We will present recent results of this research program, like extended x-ray source studies, application of 60 keV x-rays for direct density measurements and isentropic compression experiments.
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