Isochoric Heating of Solid Aluminum by Ultrashort Laser Pulses Focused on a Tamped Target

We have studied the K-shell emission of an Al plasma which was generated by focusing a high contrast 150 fs laser pulse at a wavelength of 395 nm and intensity of 5×10¹⁷W/cm² on a flat Al target tamped by a thin surface layer of MgO. The measured resonance lines ( Ly_α, He_α, and He_β) and their Li-like and He-like satellites are extremely broadened and show a red polarization shift. Analysis of the Ly_α and He_β satellites yields an electron temperature of ≈300eV and an electron density of (5--10)×10²³cm^-3.