Enhanced electron trapping andγray emission by ultra-intense laser irradiating a near-critical-density plasma filled gold cone

Abstract

The radiation trapping effect (RTE) of electrons in the interaction of an ultra-intense laser and a nearcritical-density plasma-filled gold cone is numerically investigated by using the particle-in-cell code EPOCH. It is found that, by using the cone, the threshold laser intensity for electron trapping can be significantly decreased. The trapped electrons located behind the laser front and confined near the laser axis oscillate significantly in the transverse direction and emit high-energy γ photons in the forward direction. With parameters optimized, a narrow γ photon angular distribution and a highenergy conversion efficiency from the laser to the γ photons can be obtained. The proposed scheme may offer possibilities to demonstrate the RTE of electrons in experiments at approachable laser intensities and serve as a novel table-top γ ray source.

Dense GeV electron–positron pairs generated by lasers in near-critical-density plasmas

“…Additional simulations without the NCD plasmas and cone, respectively, indicate that the reduction of the laser threshold for the electron trapping is ultimately attributed to the nonlinear effect of the laser in the NCD plasmas-filled cone, which demonstrates the advantages of the cone structure over a plasma channel40. These trapped electrons travel almost along the laser-axis, inducing a strong poloidal self-generated magnetic field4043. This results in additional pinching effect on the electrons.…”

“…Instead of being scattered off transversely, electrons are trapped inside the laser field and perform extreme oscillations in the laser polarization direction. This is the radiation trapping effect3940, which could lead to efficient synchrotron-like γ-ray emission. However, the simple test electron model39 suggests a threshold laser amplitude required to enter this regime, that is,…”

“…The scheme takes advantage of the radiation damping and trapping effect in the near-QED regime3940. Figure 1 presents the schematic drawing of our basic configuration, where two counter-propagating laser pulses interact with the NCD plasmas inside a double-cone-targets.…”

Exploring novel target structures for manipulating relativistic laser–plasma interaction

“…It should also be noted that other structured interfaces have also been studied through simulations on enhancing the laser-to-target energy conversion efficiency and altering the incident laser pulse [24][25][26][27][28][29][30][31][32][33][34][35][36] . In our work, we propose the concept of manipulation relativistic LPI by not only enhancing the absorption efficiency but also intensifying the laser pulse itself and furthermore, creating the particle sources at demand.…”

Generation of GeV positron and γ-photon beams with controllable angular momentum by intense lasers

“…Thus the RR effect dominates and QED effects come into play, so that most electrons are efficiently trapped and accelerated inside the laser pulse instead of being expelled away, constituting a dense electron beam. Figure 4 [56,57]. Thus, the electron trapping is attributed to the RR effect together with the self-generated magnetic field around the channel dug by the CP laser in the NCD plasma.…”