Study of shock waves generation, hot electron production and role of parametric instabilities in an intensity regime relevant for the shock ignition
Authors: Antonelli L., Köster P., Folpini G., Maheut Y., Baffigi F., Cristoforetti G., Labate L., Levato T., Gizzi L.A., Consoli F., De Angelis R., Kalinowska Z., Chodukowski T., Rosinski M., Parys P., Pisarczyk T., Raczka P., Ryc L., Badziak J., Wolowski J., Smid M., Renner O., Krousky E., Pfeifer M., Skala J., Ullschmied J., Nicolaï P., Ribeyre X., Shurtz G., Atzeni S., Marocchino A., Schiavi A., Spindloe C., Dell T.O., Rhee Y.J., Richetta M., Batani D.
Autors Affiliation: University of Rome Tor Vergata, Rome, Italy; Université Bordeaux 1, CNRS, CEA, CELIA (Centre Lasers Intenses et Applications), UMR 5107, Talence, F-33405, France; Intense Laser Irradiation Laboratory, INO-CNR, Pisa, Italy; Institute of Physics, ASCR, Prague, Czech Republic; ENEA-Euratom, Frascati, Italy; Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland; Institute of Plasma Physics, Prague, Czech Republic; Dipartimento SBAI, Univ. di Roma la Sapienza and CNISM, Italy; Scitech Precision, Rutherford Appleton Laboratory, United Kinkdom, United Kingdom; Nuclear Data Center, KAERI, United Kingdom
Abstract: We present experimental results at intensities relevant to Shock Ignition obtained at the sub-ns Prague Asterix Laser System in 2012. We studied shock waves produced by laser-matter interaction in presence of a pre-plasma. We used a first beam at 1? (1315 nm) at 7 x 1013 W/cm2 to create a pre-plasma on the front side of the target and a second at 3? (438 nm) at ~ 1016 W/cm2 to create the shock wave. Multilayer targets composed of 25 (or 40 m) of plastic (doped with Cl), 5 m of Cu (for K diagnostics) and 20 m of Al for shock measurement were used. We used X-ray spectroscopy of Cl to evaluate the plasma temperature, K imaging and spectroscopy to evaluate spatial and spectral properties of the fast electrons and a streak camera for shock breakout measurements. Parametric instabilities (Stimulated Raman Scattering, Stimulated Brillouin Scattering and Two Plasmon Decay) were studied by collecting the back scattered light and analysing its spectrum. Back scattered energy was measured with calorimeters. To evaluate the maximum pressure reached in our experiment we performed hydro simulations with CHIC and DUED codes. The maximum shock pressure generated in our experiment at the front side of the target during laser-interaction is 90 Mbar. The conversion efficiency into hot electrons was estimated to be of the order of ~ 0.1% and their mean energy in the order ~50 keV.
More Information: Inertial Fusion Energy Forum; Institut Lasers et Plasmas; Osaka University, Institute of Laser Engineering; The Fund Project of the Commemorative Organization for the Japan World Exposition \’70; University of CaliforniaKeyWords: Brillouin scattering; Fusion reactions; Hot electrons; Inertial confinement fusion; Laser fusion; Shock waves; X ray spectroscopy, Electron production; Laser-matter interactions; Multilayer targets; Parametric instabilities; Plasma temperature; Prague asterix laser systems; Scattering , stimulated; Spectral properties, Plasma diagnostics