Simultaneous X-ray and XUV absorption measurements in nickel laser-produced plasma close to LTE

M. Dozières (1) , F. Thais (2, 3) , S. Bastiani-Ceccotti (4) , T. Blenski (3) , M. Comet (5) , F. Condamine (4) , J. Fariaut (6) , F. Gilleron (6) , D. Gilles (2, 3) , J. C. Pain (6) , M. Poirier (2, 3) , C. Reverdin (6) , F. Rosmej (4) , V. Silvert (6) , G. Soullié (6) , B. Villette (7)

1 UC San Diego - University of California [San Diego]
2 MHDE - Matière à Haute Densité d'Energie
3 LIDyl - Laboratoire Interactions, Dynamiques et Lasers (ex SPAM)
4 LULI - Laboratoire pour l'utilisation des lasers intenses
5 LDG - Laboratoire de Détection et de Géophysique (CEA)
6 DAM/DIF - DAM Île-de-France
7 DAM - Direction des Applications Militaires

We present an experiment performed in 2016 at the LULI2000 laser facility in which X-ray and XUV absorption structures of nickel hot plasmas were measured simultaneously. Such experiments may provide stringent tests of the accuracy of plasma atomic-physics codes used to the modeling of plasmas close to local thermodynamic equilibrium. The experimental setup relies on a symmetric heating of the sample foil by two gold hohlraums in order to reduce the spatial gradients. The plasma conditions are characterized by temperatures between 10 and 20 eV and densities of the order of 10$^{−3}$ g/cm $^3$-10$^{−2}$ g/cm$^3$. For the X-ray part, we investigate the 2p-3d and 2p-4d transitions, and for the XUV part, we recorded the $\Delta$n = 0 (n = 3) transitions, which present a high sensitivity to plasma temperature. These latter transitions are of particular interest because, in mid-Z plasmas, they dominate the Planck and Rosseland mean opacities. Measured spectra are compared to calculations performed using the hybrid opacity code SCO-RCG and the Flexible Atomic Code (FAC). The influence of a spectator electron on the calculated spectra is analyzed using the latter code.

Keywords: Laser experimen; Absorption spectroscopy; Atomic physics; t LTE plasma; Opacity; X-ray

Domains: Plasma Physics [physics.plasm-ph]

M. Dozières, F. Thais, S. Bastiani-Ceccotti, T. Blenski, M. Comet, et al.. Simultaneous X-ray and XUV absorption measurements in nickel laser-produced plasma close to LTE. High Energy Density Physics, 2019, 31, pp.83-91. ⟨10.1016/j.hedp.2019.03.007⟩. ⟨cea-02293084⟩