ABSTRACT
It is possible using current high-intensity laser facilities to reach the quantum radiation reaction regime for energetic electrons. An experiment using a wakefield accelerator to drive GeV electrons into a counterpropagating laser pulse would demonstrate the increase in the yield of high-energy photons caused by the stochastic nature of quantum synchrotron emission: we show that a beam of 10(9) 1 GeV electrons colliding with a 30 fs laser pulse of intensity 10(22) W cm(-2) will emit 6300 photons with energy greater than 700 MeV, 60× the number predicted by classical theory.
ABSTRACT
In simulations of a 10 PW laser striking a solid, we demonstrate the possibility of producing a pure electron-positron plasma by the same processes as those thought to operate in high-energy astrophysical environments. A maximum positron density of 10(26) m(-3) can be achieved, 7 orders of magnitude greater than achieved in previous experiments. Additionally, 35% of the laser energy is converted to a burst of γ rays of intensity 10(22) W cm(-2), potentially the most intense γ-ray source available in the laboratory. This absorption results in a strong feedback between both pair and γ-ray production and classical plasma physics in the new "QED-plasma" regime.
ABSTRACT
A novel absorption mechanism for linearly polarized lasers propagating in relativistically underdense solids in the ultrarelativistic (a ~ 100) regime is presented. The mechanism is based on strong synchrotron emission from electrons reinjected into the laser by the space charge field they generate at the front of the laser pulse. This laser absorption, termed reinjected electron synchrotron emission, is due to a coupling of conventional plasma physics processes to quantum electrodynamic processes in low density solids at intensities above 10(22) W/cm(2). Reinjected electron synchrotron emission is identified in 2D QED-particle-in-cell simulations and then explained in terms of 1D QED-particle-in-cell simulations and simple analytical theory. It is found that between 1% (at 10(22) W/cm(2)) and 14% (at 8 × 10(23) W/cm(2)) of the laser energy is converted into gamma ray photons, potentially providing an ultraintense future gamma ray source.
ABSTRACT
Relativistic current sheets have been proposed as the sites of dissipation in pulsar winds, jets in active galaxies, and other Poynting flux dominated flows. It is shown that the steady versions of these structures differ from their nonrelativistic counterparts because they do not permit transformation to a de Hofmann-Teller frame with zero electric field. Instead, their generic form is that of a true neutral sheet with no linking magnetic field component normal to the sheet. The maximum energy to which such structures can accelerate particles is derived, and used to compute the maximum frequency of the subsequent synchrotron radiation. This can be substantially in excess of standard estimates. In the magnetically driven gamma-ray burst scenario, acceleration of electrons is possible to energies sufficient to enable photon-photon pair production after an inverse Compton scattering event.
