Electron Temperature Measurements of Solid Density Plasmas Produced by Intense Ultrashort Laser Pulses

We report the first spatially and temporally localized measurements of 500 eV electron temperatures in solid density Al plasmas generated by a $3\times {10}^{17}\mathrm{W}/{\mathrm{cm}}^2$, 170 fs laser. Expansion velocities of marker layers from various depths are sampled with mass-resolved ion time-of-flight spectroscopy. Hydrodynamic simulations relate the measured velocities to the sound speed, determining the temperature along the central axis of the plasma. Results are consistent with conductive heating of the first 1000 Å.