Direct evidence of strongly inhomogeneous energy deposition in target heating with laser-produced ion beams

E. Brambrink (1) , T. Schlegel (2) , G. Malka (3) , K. U. Amthor (4) , M. M. Aléonard (3) , G. Claverie (3) , M. Gerbaux (3) , F. Gobet (3) , F. Hannachi (3) , V. Méot (5) , Pierre Morel (5) , P. Nicolai (6) , J. N. Scheurer (3) , M. Tarisien (3) , V. Tikhonchuk (6) , P. Audebert (1)

1 LULI - Laboratoire pour l'utilisation des lasers intenses
2 GSI - Helmholtz zentrum für Schwerionenforschung GmbH
3 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
4 IOQ - Institut für Optik und Quantenelektronik
5 DAM/DIF - DAM Île-de-France
6 CELIA - Centre d'Etudes Lasers Intenses et Applications

We report on strong nonuniformities in target heating with intense, laser-produced proton beams. The observed inhomogeneity in energy deposition can strongly perturb equation of state EOS measurements with laser-accelerated ions which are planned in several laboratories. Interferometric measurements of the target expansion show different expansion velocities on the front and rear surfaces, indicating a strong difference in local temperature. The nonuniformity indicates at an additional heating mechanism, which seems to originate from electrons in the keV range.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Physique des plasmas [physics.plasm-ph]

E. Brambrink, T. Schlegel, G. Malka, K. U. Amthor, M. M. Aléonard, et al.. Direct evidence of strongly inhomogeneous energy deposition in target heating with laser-produced ion beams. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, 2007, 75, pp.065401. ⟨10.1103/PhysRevE.75.065401⟩. ⟨in2p3-00152506⟩