Energetic protons generated by ultrahigh contrast laser pulses interacting with ultrathin targets
- LULI, Ecole Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France)
- 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)
- Departement de Physique Theorique et Appliquee, CEA-DIF, 91680 Bruyeres-le-Chatel (France)
- School of Mathematics and Physics, The Queen's University, Belfast (United Kingdom)
- Physics Department, MS-220, University of Nevada, Reno, Nevada 89557 (United States)
- Institut fuer Laser und Plasma Physik, Heinrich-Heine-Universitaet Duesseldorf, Universitaetstrasse 1, 40225 Duesseldorf (Germany)
- INRS-Energie et Materiaux, 1650 bd. L. Boulet, J3X1S2 Varennes, Quebec (Canada)
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.
- OSTI ID:
- 20974861
- Journal Information:
- Physics of Plasmas, Vol. 14, Issue 3; Other Information: DOI: 10.1063/1.2480610; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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