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Title: Onset of diffuse reflectivity and fast electron flux inhibition in 528-nm-laser{endash}solid interactions at ultrahigh intensity

Abstract

Using a high-power femtosecond frequency-doubled Nd:glass laser system with a contrast ratio of 10{sup 12}, the interaction between light and matter up to intensities of 10{sup 19} Wthinspcm{sup {minus}2}has been investigated. The absorption of the laser light in solid aluminum is almost independent of the polarization, peaks at about 25{degree}, and reaches values of almost 45{percent}. Assuming an exponential electron distribution, a temperature of 420 keV at 4{times}10{sup 18} Wthinspcm{sup {minus}2}was measured. These experiments and the detection of the hard-x-ray radiation (60 keV{endash}1 MeV) implied a conversion efficiency of 10{sup {minus}4}{endash}10{sup {minus}3} into suprathermal electrons. A second low-energy electron distribution either with trajectories mainly parallel to the target surface or with a reduced penetration depth due to flux inhibition was also inferred from K{alpha} line radiation measurements. {copyright} {ital 1997} {ital The American Physical Society}

Authors:
; ;  [1]; ; ; ; ;  [2]; ;  [3]
  1. Institut fuer Optik und Quantenelektronik, Friedrich-Schiller-Universitaet, Max-Wien-Platz 1, D-07743 Jena (Germany)
  2. Max-Planck-Arbeitsgruppe Roentgenoptik an der Friedrich-Schiller-Universitaet, Max-Wien-Platz 1, D-07743 Jena (Germany)
  3. Commissariat a lEnergie Atomique, Centre dEtudes de Limeil-Valenton, 94195 Villeneuve-Saint-Georges Cedex (France)
Publication Date:
OSTI Identifier:
632552
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics; Journal Volume: 56; Journal Issue: 4; Other Information: PBD: Oct 1997
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; LASER-PRODUCED PLASMA; ALUMINIUM; LIGHT SCATTERING; MATTER; ABSORPTION; POLARIZATION; ELECTRONS; DISTRIBUTION; PENETRATION DEPTH; INHIBITION; RADIATIONS; INERTIAL CONFINEMENT; ELECTRON DENSITY; PLASMA SIMULATION

Citation Formats

Feurer, T., Theobald, W., Sauerbrey, R., Uschmann, I., Altenbernd, D., Teubner, U., Gibbon, P., Foerster, E., Malka, G., and Miquel, J.L. Onset of diffuse reflectivity and fast electron flux inhibition in 528-nm-laser{endash}solid interactions at ultrahigh intensity. United States: N. p., 1997. Web. doi:10.1103/PhysRevE.56.4608.
Feurer, T., Theobald, W., Sauerbrey, R., Uschmann, I., Altenbernd, D., Teubner, U., Gibbon, P., Foerster, E., Malka, G., & Miquel, J.L. Onset of diffuse reflectivity and fast electron flux inhibition in 528-nm-laser{endash}solid interactions at ultrahigh intensity. United States. doi:10.1103/PhysRevE.56.4608.
Feurer, T., Theobald, W., Sauerbrey, R., Uschmann, I., Altenbernd, D., Teubner, U., Gibbon, P., Foerster, E., Malka, G., and Miquel, J.L. 1997. "Onset of diffuse reflectivity and fast electron flux inhibition in 528-nm-laser{endash}solid interactions at ultrahigh intensity". United States. doi:10.1103/PhysRevE.56.4608.
@article{osti_632552,
title = {Onset of diffuse reflectivity and fast electron flux inhibition in 528-nm-laser{endash}solid interactions at ultrahigh intensity},
author = {Feurer, T. and Theobald, W. and Sauerbrey, R. and Uschmann, I. and Altenbernd, D. and Teubner, U. and Gibbon, P. and Foerster, E. and Malka, G. and Miquel, J.L.},
abstractNote = {Using a high-power femtosecond frequency-doubled Nd:glass laser system with a contrast ratio of 10{sup 12}, the interaction between light and matter up to intensities of 10{sup 19} Wthinspcm{sup {minus}2}has been investigated. The absorption of the laser light in solid aluminum is almost independent of the polarization, peaks at about 25{degree}, and reaches values of almost 45{percent}. Assuming an exponential electron distribution, a temperature of 420 keV at 4{times}10{sup 18} Wthinspcm{sup {minus}2}was measured. These experiments and the detection of the hard-x-ray radiation (60 keV{endash}1 MeV) implied a conversion efficiency of 10{sup {minus}4}{endash}10{sup {minus}3} into suprathermal electrons. A second low-energy electron distribution either with trajectories mainly parallel to the target surface or with a reduced penetration depth due to flux inhibition was also inferred from K{alpha} line radiation measurements. {copyright} {ital 1997} {ital The American Physical Society}},
doi = {10.1103/PhysRevE.56.4608},
journal = {Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics},
number = 4,
volume = 56,
place = {United States},
year = 1997,
month =
}
  • We report one of the first measurements of induced heating due to the transport of a fast electron beam generated by an ultrashort pulse laser interaction with solid targets. Rear-side optical reflectivity and emissivity have been used as diagnostics for the size and temperature of the heated zone. A narrow spot has been observed of the order of the laser focus size. Values up to {approx}10 eV at the target back surface were inferred from the experimental data and compared with the predictions of a hybrid collisional-electromagnetic transport simulation.
  • The interaction of an ultraintense laser pulse with an overcritical collisionless plasma at normal incidence is investigated with 1.5 dimensional particle-in-cell simulations. Laser absorption and hot electron energy are reported for a large range of intensities and plasma densities. We observe a strong dependence of the electron temperature on the plasma density profile, and a transition between two different heating mechanisms when the gradient length is varied. For sharp edged profiles, the electron temperature is well below the laser ponderomotive potential. {copyright} {ital 1997} {ital The American Physical Society}
  • We present experimental results on fast-electron energy deposition into solid targets in ultrahigh intensity laser-matter interaction. X-ray K{alpha} emission spectroscopy with absolute photon counting served to diagnose fast-electron propagation in multilayered targets. Target heating was measured from ionization-shifted K{alpha} emission. Data show a 200 {mu}m fast-electron range in solid Al. The relative intensities of spectrally shifted Al K{alpha} lines imply a mean temperature of a few tens of eV up to a 100 {mu}m depth. Experimental results suggest refluxing of the electron beam at target rear side. They were compared with the predictions of both a collisional Monte Carlo andmore » a collisional-electromagnetic, particle-fluid transport code. The validity of the code modeling of heating in such highly transient conditions is discussed.« less
  • Observations of multiphoton scattering of electrons born in a high-intensity laser focus are extended to intensities at which the relativistic mass shift associated with the quiver motion must be taken into account. {copyright} {ital 1996 Optical Society of America.}