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Title: Laser-to-hot-electron conversion limitations in relativistic laser matter interactions due to multi-picosecond dynamics

High-energy short-pulse lasers are pushing the limits of plasma-based particle acceleration, x-ray generation, and high-harmonic generation by creating strong electromagnetic fields at the laser focus where electrons are being accelerated to relativistic velocities. Understanding the relativistic electron dynamics is key for an accurate interpretation of measurements. We present a unified and self-consistent modeling approach in quantitative agreement with measurements and differing trends across multiple target types acquired from two separate laser systems, which differ only in their nanosecond to picosecond-scale rising edge. Insights from high-fidelity modeling of laser-plasma interaction demonstrate that the ps-scale, orders of magnitude weaker rising edge of the main pulse measurably alters target evolution and relativistic electron generation compared to idealized pulse shapes. This can lead for instance to the experimentally observed difference between 45 MeV and 75 MeV maximum energy protons for two nominally identical laser shots, due to ps-scale prepulse variations. Our results show that the realistic inclusion of temporal laser pulse profiles in modeling efforts is required if predictive capability and extrapolation are sought for future target and laser designs or for other relativistic laser ion acceleration schemes.
Authors:
; ; ; ; ;  [1] ;  [2] ; ; ;  [3] ;  [4] ;  [5]
  1. Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
  2. Institute for Fusion Studies, The University of Texas, Austin, Texas 78712 (United States)
  3. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
  4. Helmholtz Zentrum Dresden-Rossendorf, 01328 Dresden (Germany)
  5. Voss Scientific, Albuquerque, New Mexico 87108 (United States)
Publication Date:
OSTI Identifier:
22408353
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 4; Other Information: (c) 2015 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; ACCELERATION; ELECTROMAGNETIC FIELDS; ELECTRONS; HARMONIC GENERATION; INTERACTIONS; LASERS; MEV RANGE; PLASMA; PROTONS; PULSE SHAPERS; PULSES; RELATIVISTIC RANGE; X RADIATION