Creation of hot dense matter in short-pulse laser-plasma interaction with tamped titanium foils

• Published in: Physics of plasmas 2007-10, Vol.14 (10)
• Main Authors: Chen, S. N., Gregori, G., Patel, P. K., Chung, H.-K., Evans, R. G., Freeman, R. R., Garcia Saiz, E., Glenzer, S. H., Hansen, S. B., Khattak, F. Y., King, J. A., Mackinnon, A. J., Notley, M. M., Pasley, J. R., Riley, D., Stephens, R. B., Weber, R. L., Wilks, S. C., Beg, F. N.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALUMINIUM; COMPARATIVE EVALUATIONS; ELECTRON TEMPERATURE; FOILS; HYDRODYNAMICS; IONS; LASERS; LAYERS; PLASMA; PLASMA HEATING; PLASMA PRODUCTION; PULSES; THIN FILMS; TITANIUM; X-RAY SPECTRA
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/1.2777118

Dense titanium plasma has been heated to an electron temperature up to 1300 eV with a 100 TW , high intensity short-pulse laser. The experiments were conducted using Ti foils ( 5 μ m thick) sandwiched between layers of either aluminum (1 or 2 μ m thick) or plastic ( 2 μ m thick) to prevent the effects of prepulse. Targets of two different sizes, i.e., 250 × 250 μ m 2 and 1 × 1 mm 2 were used. Spectral measurements of the Ti inner-shell emission, in the region between 4 and 5 keV , were taken from the front-side (i.e., the laser illuminated side) of the target. The data show large shifts in the K α emission from open-shell ions, suggesting bulk heating of the sample at near solid density, which was largest for reduced mass targets. Comparison with collisional radiative and 2D radiation hydrodynamics codes indicates a peak temperature of T e , peak = 1300 eV of solid titanium plasma in ∼ 0.2 μ m thin layer. Higher bulk temperature ( T e , bulk = 100 eV ) for aluminum tamped compared to CH tamped targets ( T e , bulk = 40 eV ) was observed. A possible explanation for this difference is described whereby scattering due to the nuclear charge of the tamping material leads to modified electron transport behavior.