J Osterhoff

Publications (5)2.26 Total impact

• Source

  Available from: utexas.edu

  Article: Angular distribution of neutrons from deuterated cluster explosions driven by femtosecond laser pulses.

  F Buersgens, K W Madison, D R Symes, R Hartke, J Osterhoff, W Grigsby, G Dyer, T Ditmire
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  ABSTRACT: We have studied experimentally the angular distributions of fusion neutrons from plasmas of multi-keV ion temperature, created by 40 fs, multi-TW laser pulses in dense plumes of D2 and CD4 clusters. A slight anisotropy in the neutron emission is observed. We attribute this anisotropy to the fact that the differential cross section for DD fusion is anisotropic even at low collision energies, and this, coupled with the geometry of the gas jet target, leads to beam-target neutrons that are slightly directed. The qualitative features of this anisotropy are confirmed by Monte Carlo simulations.
  Physical Review E 08/2006; 74(1 Pt 2):016403. · 2.26 Impact Factor
• Conference Proceeding: Ultra high intensity laser launched radiative shock waves related to supernova remnant formation

  J Osterhoff, D R Symes, A D Edens, T Ditmire
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  ABSTRACT: We show evidence for strongly radiative laser produced shocks in cluster media. In addition blast front thinning suggests the onset of accessing a regime possibly susceptible for hydrodynamic instabilities related to supernova remnant formation.
  Quantum Electronics and Laser Science Conference, 2005. QELS '05; 06/2005
• Article: Investigations of laser-driven radiative blast waves in clustered gases

  D.R. Symes, M. Hohenberger, J. Lazarus, J. Osterhoff, A.S. Moore, R.R. Fäustlin, A.D. Edens, H.W. Doyle, R.E. Carley, A. Marocchino, J.P. Chittenden, A.C. Bernstein, E.T. Gumbrell, Mike Dunne, R.A. Smith, T. Ditmire
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  ABSTRACT: Radiative blast waves can be created by focusing intense laser pulses into highly absorbing clustered gases. By considering the plasma conditions these shocks can be categorized as optically thin radiative shocks, a regime of particular interest for laboratory astrophysics experiments. A periodic spatial modulation is introduced to the shock front in order to investigate instability and shock collisions. Hydrodynamic simulations are presented which are in qualitative agreement with the experimental results. A technique to perform a single shot measurement of the entire shock trajectory and the possibility to detect oscillations in the shock velocity is discussed.
  High Energy Density Physics.
• Article: Radiative shell thinning in intense laser-driven blast waves

  J Osterhoff, AD Edens, T Ditmire, DR Symes, AS Moore, E Hellewell
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  ABSTRACT: The structural evolution of blast waves launched by intense laser pulses in gases is investigated. These blast waves exhibit significant energy loss through radiation while propagating in xenon as evidenced by interferometric imaging revealing radiative precursors and deceleration parameters well below those of an energy conserving wave. Thinning of the blast wave shell from radiative cooling is observed through comparison of shocks launched in gases of differing atomic number. Shell thinning is also measured when the gas density is altered, indicating the influence of conditions within the preshock medium. These results are compared to radiative-hydrodynamic simulations.
• Article: Production of periodically modulated laser-driven blast waves in a clustering gas

  D.R. Symes, J. Osterhoff, R. Fäustlin, M. Maurer, A.C. Bernstein, A.S. Moore, E.T. Gumbrell, A.D. Edens, R.A. Smith, T. Ditmire
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  ABSTRACT: To study hydrodynamic behavior on thin shell high Mach number blast waves, experiments have been performed in which spatially tailored shock waves have been launched in a gas of clusters using an intense 35 fs laser pulse. The target medium was first modified by destroying clusters in specific locations using a spatially modulated laser focus. Under subsequent intense laser irradiation, the efficient absorption properties of the remaining clustered regions compared to those regions with no clusters led to a pattern of hot and cold plasma resulting in a cylindrical blast wave with a periodic modulation imprinted on the shock front. This technique may provide a method for studying thin shell instabilities in strongly radiative blast waves.
  High Energy Density Physics.