EPJ Web of Conferences (Nov 2013)

Study of shock-coalescence on the LIL laser facility

  • Debras G.,
  • Courtois C.,
  • Lambert F.,
  • Brygoo S.,
  • Duval A.,
  • Darbon S.,
  • Villette B.,
  • Masclet-Gobin I.,
  • Philippe F.,
  • Casner A.,
  • Seytor P.,
  • Videau L.,
  • Graillot H.,
  • Chies T.,
  • Henry O.,
  • Raffestin D.,
  • Chicanne C.

DOI
https://doi.org/10.1051/epjconf/20135902006
Journal volume & issue
Vol. 59
p. 02006

Abstract

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We use the LIL (Ligne d'Intégration Laser) facility to study the coalescence of two planar shocks in an indirectly-driven planar sample of polystyrene. This experiment represents the preliminary stage of the future shock-timing campaign for the Laser Megajoule (LMJ). The main objectives are to validate the experimental concept and to test the numerical simulations. We used a gold spherical hohlraum to convert into X-ray the 351 nm wavelength laser pulse and to initiate the two shocks in the sample. To access time resolved shock velocities and temperature, we used two rear-side diagnostics: a VISAR (Velocity Interferometer System for Any Reflection) working at two different wavelengths and a streaked optical self-emission diagnostic. We observed the coalesced shock, in good agreement with the numerical simulations. We also observed a loss of signal during the first nanoseconds probably due to sample heating from the hohlraum X-ray flux.