Study of iron under high pressure conditions using isentropic compression*

Equation of state (EOS) data of iron and iron alloys is important for a deeper understanding of the dynamic of the earth inner core, which requires off-Hugoniot data ($\sim $3 Mbar, 5000 K), especially in the range of the high pressure-melting curve. Isentropic compression with high-energy lasers is a promising approach to reach high-pressure off-Hugoniot states. Presently two techniques are used: an indirect approach using the ramp load of a foil exploded by a laser (reservoir technique) [1] and direct ramping of the ablation pressure by shaping the temporal profile of the laser [2]. We are presenting results on isentropic compression experiments of iron using the reservoir technique and direct laser shaping. [1] Smith, Phys. Plasmas 14, 057105 (2007) [2] Swift, PRE 71, 066401 (2005)