Time Resolved Ni K Shell Spectroscopy of Nanowire Arrays Irradiated at Highly Relativistic Intensities

H. SONG; CAPELUTO, M G; S WANG; OTROS PARTICIPANTES, VER LISTA EN ADJUNTO; HOLLINGER, R; A. MOREAU

Conferencia; 62nd Annual Meeting of the APS Division of Plasma Physics; 2020

Ni K shell emission from near-solid density nanowire arrays and solid density foils was spectrally and temporally resolved using an x-ray streak camera with sub-picosecond temporal resolution coupled to a Von Hamos crystal spectrometer. The targets were 100nm diameter Ni arrays with various fractions of solid density (7%, 15% and 24%) and were irradiated with high contrast(>1012), = 400nm, 45fs laser pulses focused to intensities >1021Wcm−2 . These results were compared to the emission from solid density Ni foils. The duration of the Ni He- line was measured to decrease from 21 ps for an initial electron density of 1.6x1023cm−3 to 5 ps for a solid foil with an initial electron density of 2.4x1024cm−3 . The increased time duration of the x-ray emission from the lower density nanowire arrays is shown to be a consequence of the increased volumetric heating of the plasma which delays the hydrodynamic expansion. These results are in good agreement withhybrid three-dimensional particle-in-cell/radiative hydrodynamic simulations.