Electron–positron cascades in multiple-laser optical traps

Abstract

We present an analytical and numerical study of multiple-laser QED cascades induced with linearly polarised laser pulses. We analyse different polarisation orientations and propose a configuration that maximises the cascade multiplicity and favours the laser absorption. We generalise the analytical estimate for the cascade growth rate previously calculated in the field of two colliding linearly polarised laser pulses and account for multiple laser interaction. The estimate is verified by a comprehensive numerical study of four-laser QED cascades across a range of different laser intensities with QED PIC module of OSIRIS. We show that by using four linearly polarised 30 fs laser pulses, one can convert more than 50% of the total energy to gamma-rays already at laser intensity I 10 24 W/cm 2 . In this configuration, the laser conversion efficiency is higher compared with the case with two colliding lasers.

Charged particle dynamics in multiple colliding electromagnetic waves. Survey of random walk, Lévy flights, limit circles, attractors and structurally determinate patterns

“…They are structurally determinate patterns, as if made by tiles, formed in the high field amplitude limit when the radiation friction force drastically modifies the charged particle dynamics in the electromagnetic field as can be distinctly seen in figures 18, 20, 27 and 28. As for the possible practical implications of these findings, these 'crystal-like' patterns are expected to be seen in the spatial distribution of the γ -rays emitted by the electrons irradiated by the multiple high power laser pulses, which has been noticed in Gong et al (2017) and Vranic et al (2017).…”

“…In addition, as has been noted above, in a standing wave formed by two colliding laser pulses, the resulting electromagnetic (EM) field configuration facilitates QED effects (see Bulanov et al 2004aBulanov et al , 2006Bulanov et al , 2010b. Computer simulations presented in Gonoskov et al (2016), Gong et al (2017), Vranic et al (2017) show that the MCLP concept can be beneficial for realizing such important laser-matter interaction regimes as, for example, the electron-positron pair production via the Breit-Wheeler process (see Vranic et al 2017) and the high efficiency γ -ray flash generation due Charged particle dynamics in colliding electromagnetic waves 3 to nonlinear Thomson or multi-photon Compton scattering, as shown in Gonoskov et al (2016), Gong et al (2017). Another configuration for the generation of a γ -ray flash is a single laser pulse irradiating an overdense plasma target (see Nakamura et al 2012;Ridgers et al 2012;Corvan, Zepf & Sarri 2016;Levy et al 2016).…”

Radiation reaction in electron–beam interactions with high-intensity lasers

“…Radiation reaction induces a rich set of dynamics in this configuration [144][145][146][147]. The fact that standing waves can do work in reaccelerating the particles after they recoil means that, at intensities 10 24 Wcm −2 , the emitted photons seed avalanches of electron-positron pair creation [94]; this intensity threshold is lowered in suitable multibeam setups [148][149][150]. The case of optimal focussing is achieved in a dipole field [151], where the peak a 0 780P 1/2 [PW] [152].…”

Identifying the electron–positron cascade regimes in high-intensity laser-matter interactions

“…Right: predicted absorption fraction of the laser energy (colour scale) and 2D simulation results (dots) at t = 42 fs. geometry, recent work has shown that more complicated laser pulses and geometries or high atomic number targets could be favourable to cascades [55][56][57][58]. Again we would not expect a more complicated laser pulse geometry to qualitatively change the cascade regimes.…”