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Title: Energetic protons generated by ultrahigh contrast laser pulses interacting with ultrathin targets

Abstract

A regime of laser acceleration of protons, which relies on the interaction of ultrahigh contrast laser pulses with ultrathin targets, has been validated using experiments and simulations. Proton beams were accelerated to a maximum energy of {approx}7.3 MeV from targets as thin as 30 nm irradiated at 10{sup 18} W cm{sup -2} {mu}m{sup 2} (1 J, 320 fs) with an estimated peak laser pulse to pedestal intensity contrast ratio of 10{sup 11}. This represents nearly a tenfold increase in proton energy compared to the highest energies obtainable using non contrast enhanced pulses and thicker targets (>5 {mu}m) at the same intensity. To obtain similar proton energy with thicker targets and the same laser pulse duration, a much higher laser intensity (i.e., above 10{sup 19} W cm{sup -2} {mu}m{sup 2}) is required. The simulations are in close agreement with the experimental results, showing efficient electron heating compared to the case of thicker targets. Rapid target expansion, allowing laser absorption in density gradients, is key to enhanced electron heating and ion acceleration in ultrathin targets.

Authors:
 [1];  [2]; ; ; ;  [1];  [3];  [4];  [5]; ;  [6]; ;  [7]; ;  [8];  [9]
  1. LULI, Ecole Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France)
  2. (Italy)
  3. LULI, Ecole Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France) and Physics Department, MS-220, University of Nevada, Reno, Nevada 89557 (United States)
  4. (France)
  5. Departement de Physique Theorique et Appliquee, CEA-DIF, 91680 Bruyeres-le-Chatel (France)
  6. School of Mathematics and Physics, The Queen's University, Belfast (United Kingdom)
  7. Physics Department, MS-220, University of Nevada, Reno, Nevada 89557 (United States)
  8. Institut fuer Laser und Plasma Physik, Heinrich-Heine-Universitaet Duesseldorf, Universitaetstrasse 1, 40225 Duesseldorf (Germany)
  9. INRS-Energie et Materiaux, 1650 bd. L. Boulet, J3X1S2 Varennes, Quebec (Canada)
Publication Date:
OSTI Identifier:
20974861
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 3; Other Information: DOI: 10.1063/1.2480610; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ABSORPTION; ACCELERATION; ELECTRONS; LASERS; LIGHT TRANSMISSION; MEV RANGE 01-10; PLASMA DENSITY; PLASMA HEATING; PROTON BEAMS; PROTONS; PULSES

Citation Formats

Antici, P., Dipartimento di Energetica, Universita di Roma 'La Sapienza', Via Scarpa 14-16, 00165 Rome, Fuchs, J., Brambrink, E., Romagnani, L., Audebert, P., D'Humieres, E., Departement de Physique Theorique et Appliquee, CEA-DIF, 91680 Bruyeres-le-Chatel, Lefebvre, E., Borghesi, M., Cecchetti, C. A., Gaillard, S., Sentoku, Y., Toncian, T., Willi, O., and Pepin, H. Energetic protons generated by ultrahigh contrast laser pulses interacting with ultrathin targets. United States: N. p., 2007. Web. doi:10.1063/1.2480610.
Antici, P., Dipartimento di Energetica, Universita di Roma 'La Sapienza', Via Scarpa 14-16, 00165 Rome, Fuchs, J., Brambrink, E., Romagnani, L., Audebert, P., D'Humieres, E., Departement de Physique Theorique et Appliquee, CEA-DIF, 91680 Bruyeres-le-Chatel, Lefebvre, E., Borghesi, M., Cecchetti, C. A., Gaillard, S., Sentoku, Y., Toncian, T., Willi, O., & Pepin, H. Energetic protons generated by ultrahigh contrast laser pulses interacting with ultrathin targets. United States. doi:10.1063/1.2480610.
Antici, P., Dipartimento di Energetica, Universita di Roma 'La Sapienza', Via Scarpa 14-16, 00165 Rome, Fuchs, J., Brambrink, E., Romagnani, L., Audebert, P., D'Humieres, E., Departement de Physique Theorique et Appliquee, CEA-DIF, 91680 Bruyeres-le-Chatel, Lefebvre, E., Borghesi, M., Cecchetti, C. A., Gaillard, S., Sentoku, Y., Toncian, T., Willi, O., and Pepin, H. Thu . "Energetic protons generated by ultrahigh contrast laser pulses interacting with ultrathin targets". United States. doi:10.1063/1.2480610.
@article{osti_20974861,
title = {Energetic protons generated by ultrahigh contrast laser pulses interacting with ultrathin targets},
author = {Antici, P. and Dipartimento di Energetica, Universita di Roma 'La Sapienza', Via Scarpa 14-16, 00165 Rome and Fuchs, J. and Brambrink, E. and Romagnani, L. and Audebert, P. and D'Humieres, E. and Departement de Physique Theorique et Appliquee, CEA-DIF, 91680 Bruyeres-le-Chatel and Lefebvre, E. and Borghesi, M. and Cecchetti, C. A. and Gaillard, S. and Sentoku, Y. and Toncian, T. and Willi, O. and Pepin, H.},
abstractNote = {A regime of laser acceleration of protons, which relies on the interaction of ultrahigh contrast laser pulses with ultrathin targets, has been validated using experiments and simulations. Proton beams were accelerated to a maximum energy of {approx}7.3 MeV from targets as thin as 30 nm irradiated at 10{sup 18} W cm{sup -2} {mu}m{sup 2} (1 J, 320 fs) with an estimated peak laser pulse to pedestal intensity contrast ratio of 10{sup 11}. This represents nearly a tenfold increase in proton energy compared to the highest energies obtainable using non contrast enhanced pulses and thicker targets (>5 {mu}m) at the same intensity. To obtain similar proton energy with thicker targets and the same laser pulse duration, a much higher laser intensity (i.e., above 10{sup 19} W cm{sup -2} {mu}m{sup 2}) is required. The simulations are in close agreement with the experimental results, showing efficient electron heating compared to the case of thicker targets. Rapid target expansion, allowing laser absorption in density gradients, is key to enhanced electron heating and ion acceleration in ultrathin targets.},
doi = {10.1063/1.2480610},
journal = {Physics of Plasmas},
number = 3,
volume = 14,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
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  • Recent significant improvements of the contrast ratio of chirped pulse amplified pulses allows us to extend the applicability domain of laser accelerated protons to very thin targets. In this framework, we propose an analytical model particularly suitable to reproducing ion laser acceleration experiments using high intensity and ultrahigh contrast pulses. The model is based on a self-consistent solution of the Poisson equation using an adiabatic approximation for laser generated fast electrons which allows one to find the target thickness maximizing the maximum proton (and ion) energies and population as a function of the laser parameters. Model furnished values show amore » good agreement with experimental data and 2D particle-in-cell simulation results.« less
  • The effects of small amounts of energy delivered at times before the peak intensity of ultrahigh-intensity ultrafast-laser pulses have been a major obstacle to the goal of studying the interaction of ultraintense light with solids for more than two decades now. We describe implementation of a practical double-plasma-mirror pulse cleaner, built into a f=10 m null telescope and added as a standard beamline feature of a 100 TW laser system for ultraintense laser-matter interaction. Our measurements allow us to infer a pulse-height contrast of 5x10{sup 11} - the highest contrast generated to date - while preserving {approx}50% of the lasermore » intensity and maintaining excellent focusability of the delivered beam. We present a complete optical characterization, comparing empirical results and numerical modeling of a double-plasma-mirror system.« less