Phase-space contraction and attractors for ultrarelativistic electrons

Abstract

Ultrashort-pulse laser intensities can reach 10(22) W/cm(2). In this case the electron motion becomes ultrarelativistic and significant bremsstrahlung occurs. The radiation causes a dissipative effect, which is called a radiation reaction. It has been shown in the literature that the radiation reaction force causes phase-space contraction when the motion of electrons in a laser field is considered. The effect of the radiation reaction force is smaller for electron propagation in the direction of a propagating plane wave compared to counterpropagation. In the case of two colliding laser beams with sufficiently large amplitudes, stochastic heating is an important process that will be influenced by the radiation reaction. It is shown here that the radiation reaction causes attractors and in certain parameter regimes electron motion converges to regular attractors. This causes a significant reduction of stochastic heating. The forms of the attractors are presented. The results confirm the general prediction of phase-space contraction and provide quantitative results for the speed of contraction as well as the type of attracted motion.

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

“…Even in the simplest MCLP case, two counter-propagating plane waves, the particle behaviour in the standing wave is quite complicated. It demonstrates regular and chaotic motion, random walk, limit circles and strange attractors as is shown by Mendonca (1983), Bauer, Mulser & Steeb (1995), Sheng et al (2002), Lehmann & Spatschek (2012, 2016, Gonoskov et al (2014), Bashinov, Kim & Sergeev (2015), Bulanov et al (2015), Esirkepov et al (2015), Jirka et al (2016), Kirk (2016). As is well known, the standing wave configuration is widely used in classical electrodynamics and in QED theory.…”

“…EM field configuration An electron interaction with an EM field formed by two counter-propagating waves has been addressed a number of times in high field theory using classical quantum electrodynamics approaches because it provides one of the basic EM configurations where important properties of a radiating electron can be revealed (e.g. see above cited publications Mendonca 1983;Di Piazza et al 2012;Lehmann & Spatschek 2012, 2016Gonoskov et al 2013Gonoskov et al , 2014Bashinov et al 2015;Bulanov et al 2015;Chang et al 2015;Esirkepov et al 2015;Lobet et al 2015;Bashinov, Kumar & Kim 2016;Grismayer et al 2016;Jirka et al 2016;Kirk 2016). Here, we present the results of the analysis of electron motion in a standing EM wave in order to compare them below with the radiating electron behaviour in a more complicated EM configuration formed by three or four waves with various polarizations.…”

Transparency of near-critical density plasmas under extreme laser intensities

“…Nowadays, the quest for exploring new physics in the near-quantum electro-dynamics (QED) regime and for important applications as ion acceleration has led to the construction of next generation laser facilities like ELI, XCEL etc [12], aiming for intensities over 10 23 W cm −2 . Several aspects of LPI can be fundamentally changed in these extreme conditions, including MeV-gamma-photon emission [13][14][15], electron cooling [16][17][18][19][20][21] and even trapping [22][23][24] of electrons due to radiation reaction (RR). Under this context, we revisit plasma transparency in the near-QED regime, because it is not only of fundamental important but also distinguishes the electron dynamics and hence the photon emission process for potential applications.…”

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.…”