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Title: Energy partition, γ-ray emission, and radiation reaction in the near-quantum electrodynamical regime of laser-plasma interaction

When extremely intense lasers (I ≥ 10{sup 22} W/cm{sup 2}) interact with plasmas, a significant fraction of the pulse energy is converted into photon emission in the multi-MeV energy range. This emission results in a radiation reaction (RR) force on electrons, which becomes important at ultrahigh intensities. Using three-dimensional particle-in-cell simulations which include a quantum electrodynamics model for the γ–photons emission, the corresponding RR force and electron-positron pair creation, the energy partition in the laser-plasma system is investigated. At sufficiently high laser amplitudes, the fraction of laser energy coupled to electrons decreases, while the energy converted to γ-photons increases. The interaction becomes an efficient source of γ-rays when I > 10{sup 24} W/cm{sup 2}, with up to 40% of the laser energy converted to high-energy photons. A systematic study of energy partition and γ-photon emission angle shows the influence of laser intensity and polarization for two plasma conditions: high-density carbon targets and a low-density hydrogen targets. We find that in the opaque region, the laser-to-photon conversion efficiency scales as I{sub 0}{sup 3/2} for linearly polarized and I{sub 0}{sup 2−2.5} for circularly polarized lasers, respectively. In the relativistically transparent regime, the power-laws merge into I{sub 0}{sup 1/2} for both polarizations and photon emission peaks in the forwardmore » direction with a relatively small divergence angle (<20°), resulting in a collimated γ-ray beam.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ; ;  [4] ;  [3] ;  [5] ;  [6]
  1. Institut für Theoretische Physik I, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf (Germany)
  2. (China)
  3. (Russian Federation)
  4. Institute of Applied Physics of the Russian Academy of Sciences, 603950 Nizhny Novgorod (Russian Federation)
  5. Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)
  6. The Ohio State University, Columbus, Ohio 43210 (United States)
Publication Date:
OSTI Identifier:
22252055
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 2; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BEAMS; ELECTRONS; LASERS; MEV RANGE; PAIR PRODUCTION; PARTITION; PHOTON EMISSION; PHOTONS; PLASMA; POSITRONS; PULSES; QUANTUM ELECTRODYNAMICS; SIMULATION