TY - JOUR

T1 - Benchmarking semiclassical approaches to strong-field QED

T2 - Nonlinear Compton scattering in intense laser pulses

AU - Blackburn, T.G.

AU - Seipt, D.

AU - Bulanov, S.S.

AU - Marklund, M.

PY - 2018/8

Y1 - 2018/8

N2 - The recoil associated with photon emission is key to the dynamics of ultrarelativistic electrons in strong electromagnetic fields, as found in high-intensity laser-matter interactions and astrophysical environments such as neutron star magnetospheres. When the energy of the photon becomes comparable to that of the electron, it is necessary to use quantum electrodynamics (QED) to describe the dynamics accurately. However, computing the appropriate scattering matrix element from strong-field QED is not generally possible due to multiparticle effects and the complex structure of the electromagnetic fields. Therefore, these interactions are treated semiclassically, coupling probabilistic emission events to classical electrodynamics using rates calculated in the locally constant field approximation. Here, we provide comprehensive benchmarking of this approach against the exact QED calculation for nonlinear Compton scattering of electrons in an intense laser pulse. We find agreement at the percentage level between the photon spectra, as well as between the models' predictions of absorption from the background field, for normalized amplitudes a0 > 5. We discuss possible routes towards improved numerical methods and the implications of our results for the study of QED cascades. © 2018 Author(s).

AB - The recoil associated with photon emission is key to the dynamics of ultrarelativistic electrons in strong electromagnetic fields, as found in high-intensity laser-matter interactions and astrophysical environments such as neutron star magnetospheres. When the energy of the photon becomes comparable to that of the electron, it is necessary to use quantum electrodynamics (QED) to describe the dynamics accurately. However, computing the appropriate scattering matrix element from strong-field QED is not generally possible due to multiparticle effects and the complex structure of the electromagnetic fields. Therefore, these interactions are treated semiclassically, coupling probabilistic emission events to classical electrodynamics using rates calculated in the locally constant field approximation. Here, we provide comprehensive benchmarking of this approach against the exact QED calculation for nonlinear Compton scattering of electrons in an intense laser pulse. We find agreement at the percentage level between the photon spectra, as well as between the models' predictions of absorption from the background field, for normalized amplitudes a0 > 5. We discuss possible routes towards improved numerical methods and the implications of our results for the study of QED cascades. © 2018 Author(s).

KW - Benchmarking

KW - Compton scattering

KW - Electrodynamics

KW - Electromagnetic fields

KW - Laser pulses

KW - Magnetosphere

KW - Numerical methods

KW - Photons

KW - Quantum electronics

KW - Classical electrodynamics

KW - Complex structure

KW - Field approximations

KW - High-intensity laser matter interaction

KW - Intense laser pulse

KW - Quantum electrodynamics

KW - Scattering matrix elements

KW - Semiclassical approaches

KW - Electromagnetic field effects

U2 - 10.1063/1.5037967

DO - 10.1063/1.5037967

M3 - Journal article

VL - 25

JO - Physics of Plasmas

JF - Physics of Plasmas

SN - 1070-664X

IS - 8

M1 - 083108

ER -