skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: 'Light Sail' Acceleration Reexamined

Abstract

The dynamics of the acceleration of ultrathin foil targets by the radiation pressure of superintense, circularly polarized laser pulses is investigated by analytical modeling and particle-in-cell simulations. By addressing self-induced transparency and charge separation effects, it is shown that for 'optimal' values of the foil thickness only a thin layer at the rear side is accelerated by radiation pressure. The simple 'light sail' model gives a good estimate of the energy per nucleon, but overestimates the conversion efficiency of laser energy into monoenergetic ions.

Authors:
 [1];  [2]; ;  [3]
  1. CNR/INFM/polyLAB, Pisa (Italy)
  2. (Italy)
  3. Dipartimento di Fisica 'Enrico Fermi', Universita di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa (Italy)
Publication Date:
OSTI Identifier:
21364627
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 103; Journal Issue: 8; Other Information: DOI: 10.1103/PhysRevLett.103.085003; (c) 2009 The American Physical Society
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 43 PARTICLE ACCELERATORS; ACCELERATION; FOILS; LASERS; RADIATION PRESSURE; SIMULATION; THIN FILMS; FILMS

Citation Formats

Macchi, Andrea, Dipartimento di Fisica 'Enrico Fermi', Universita di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa, Veghini, Silvia, and Pegoraro, Francesco. 'Light Sail' Acceleration Reexamined. United States: N. p., 2009. Web. doi:10.1103/PHYSREVLETT.103.085003.
Macchi, Andrea, Dipartimento di Fisica 'Enrico Fermi', Universita di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa, Veghini, Silvia, & Pegoraro, Francesco. 'Light Sail' Acceleration Reexamined. United States. doi:10.1103/PHYSREVLETT.103.085003.
Macchi, Andrea, Dipartimento di Fisica 'Enrico Fermi', Universita di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa, Veghini, Silvia, and Pegoraro, Francesco. 2009. "'Light Sail' Acceleration Reexamined". United States. doi:10.1103/PHYSREVLETT.103.085003.
@article{osti_21364627,
title = {'Light Sail' Acceleration Reexamined},
author = {Macchi, Andrea and Dipartimento di Fisica 'Enrico Fermi', Universita di Pisa, Largo Bruno Pontecorvo 3, I-56127 Pisa and Veghini, Silvia and Pegoraro, Francesco},
abstractNote = {The dynamics of the acceleration of ultrathin foil targets by the radiation pressure of superintense, circularly polarized laser pulses is investigated by analytical modeling and particle-in-cell simulations. By addressing self-induced transparency and charge separation effects, it is shown that for 'optimal' values of the foil thickness only a thin layer at the rear side is accelerated by radiation pressure. The simple 'light sail' model gives a good estimate of the energy per nucleon, but overestimates the conversion efficiency of laser energy into monoenergetic ions.},
doi = {10.1103/PHYSREVLETT.103.085003},
journal = {Physical Review Letters},
number = 8,
volume = 103,
place = {United States},
year = 2009,
month = 8
}
  • A new ion radiation-pressure acceleration regime, the 'leaky light sail', is proposed which uses sub-skin-depth nanometer foils irradiated by circularly polarized laser pulses. In the regime, the foil is partially transparent, continuously leaking electrons out along with the transmitted laser field. This feature can be exploited by a multispecies nanofoil configuration to stabilize the acceleration of the light ion component, supplementing the latter with an excess of electrons leaked from those associated with the heavy ions to avoid Coulomb explosion. It is shown by 2D particle-in-cell simulations that a monoenergetic proton beam with energy 18 MeV is produced by circularlymore » polarized lasers at intensities of just 10{sup 19} W/cm{sup 2}. 100 MeV proton beams are obtained by increasing the intensities to 2x10{sup 20} W/cm{sup 2}.« less
  • A scheme for producing collimated protons from laser interactions with a diamond-like-carbon + pinhole target is proposed. The process is based on radiation pressure acceleration in the multi-species light-sail regime [B. Qiao et al., Phys. Rev. Lett. 105, 155002 (2010); T. P. Yu et al., Phys. Rev. Lett. 105, 065002 (2010)]. Particle-in-cell simulations demonstrate that transverse quasistatic electric field at TV/m level can be generated in the pinhole. The transverse electric field suppresses the transverse expansion of protons effectively, resulting in a higher density and more collimated proton beam compared with a single foil target. The dependence of the proton beam divergencemore » on the parameters of the pinhole is also investigated.« less
  • The dynamics of radiation pressure acceleration in the relativistic light sail regime are analysed by means of large scale, three-dimensional (3D) particle-in-cell simulations. Differently to other mechanisms, the 3D dynamics leads to faster and higher energy gain than in 1D or 2D geometry. This effect is caused by the local decrease of the target density due to transverse expansion leading to a “lighter sail.” However, the rarefaction of the target leads to an earlier transition to transparency limiting the energy gain. A transverse instability leads to a structured and inhomogeneous ion distribution.
  • The model used to calculate Casimir forces for variously shaped conducting plates in this paper assumes the vacuum energy pervades all space and that photons randomly pop into and out of existence. While they exist, they possess energy and momentum that can be transferred by reflection as in a light sail. Quantum mechanics in the model is entirely bound up in the Casimir equation of force per unit area. This model is compared with two different experiments: that of Chen and Mohideen demonstrating lateral Casimir forces for sinusoidally corrugated spherical and flat plates and Lamoreaux demonstrating normal Casimir forces betweenmore » a conducting sphere and flat plate. The calculated forces using this model were compared to the forces obtained in these experiments as well as with calculations using the proximity force approximation. In both cases the results (when compared to the actual plates measured and calculated using non-corrected equations) were less than a few parts per thousand different for the range of separation distances used. When the model was used to calculate forces on the opposite plates, different force magnitudes were obtained seemingly indicating prospects for propellentless propulsion but requiring skeptical verification.« less
  • The stability of a light sail riding on a laser beam is analyzed both analytically and numerically. Conical sails on Gaussian beams, which have been studied in the past, are shown to be unstable without active control or additional mechanical modifications. A new architecture for a passively stable sail-and-beam configuration is proposed. The novel spherical shell design for the sail is capable of “beam riding” without the need for active feedback control. Full three-dimensional ray-tracing simulations are performed to verify our analytical results.