Pair production in counter-propagating laser beams

Abstract

Abstract. Based on an analysis of a specific electron trajectory in counterpropagating beams, Bell & Kirk (PRL 101, 200403 (2008)) recently suggested that laboratory lasers may shortly be able to produce significant numbers of electronpositron pairs. We confirm their results using an improved treatment of nonlinear Compton scattering in the laser beams. Implementing an algorithm that integrates classical electron trajectories, we then examine a wide range of laser pulse shapes and polarizations. We find that counter-propagating, linearly polarized beams, with either aligned or crossed orientation, are likely to initiate a pair avalanche at intensities of approximately 10 24 W cm −2 per beam. The same result is found by modelling one of the beams as a wave reflected at the surface of an overdense solid.

Seeded QED cascades in counterpropagating laser pulses

“…This process usually leads to QED cascades, as the pairs created reemit hard photons that decay anew in pairs, eventually resulting in an electron-positron-photon plasma. QED cascades, also referenced as electronic or electromagnetic showers [7][8][9][10] when the external field is purely magnetic, have been theoretically studied in different electromagnetic configurations [11][12][13][14]. Notably, Bell & Kirk [15] suggested a judicious configuration comprising two circularly polarized counter propagating lasers with some electrons in the interaction region to seed the cascade.…”

Radiation-Reaction Trapping of Electrons in Extreme Laser Fields

“…It leads to much lower electron energies than the ones one would expect neglecting RR [14][15][16][17][18][19][20][21][22][23]. It has also been noticed that free electrons can be attracted to the positions of electric field peaks in the near-QED regime by creating a standing wave structure with multiple lasers [24][25][26].…”

“…Unlike in the non-QED regime, electrons can be transversely trapped by the laser field instead of being pushed away. Different from the standing EM wave cases [24][25][26], where electrons are mostly confined in a small volume of the laser wavelength, a traveling wave is considered here. The spatial period and the oscillation amplitude are typically large as compared with the laser wavelength.…”

Radiating electron source generation in ultraintense laser-foil interactions

“…For χ e ∼ 1, the quantum nature of the radiation, with emitted photons having energy comparable to the electron energy, leads to discontinuous particle trajectories with significant recoils and non-negligible electron-positron pair creation [25][26][27][28][29]. In the semi-classical regime χ e ∼ 0.1 a continuous treatment of the radiation emission is still possible, although the expressions for the total radiated power and energy spectra need to be corrected [25,26,30].…”

“…It uses the Vlasov-Maxwell system with the inclusion of quantum processes such as the synchrotron gamma-ray photon emission from radiating electrons into the electromagnetic fields and pair production [30,[33][34][35]. The particles of the plasma (electrons, positrons and ions) are described by the quasi-classical model of Baier and Katkov [36] which means that the particles experience the Lorentz force and photon emission is computed with an emission probability [34,35], inducing the lost electron momentum.…”