Generation And Manipulation Of Bright ? Ray And Positrons By Ultra-short Ultra-intense Laser Solid Target Interaction

High field laser physics is an advanced science that emerged over the past two decades with the rapid development of ultra-short ultra-intense laser technology.Especially with the advent of the Chirped Pulse Amplification technique?CPA?,the intensity of the laser pulse arise from the initial 10¹55 W/cm² to approximately 10²22 W/cm²,and the pulse duration is also compressed to femtosecond?fs?.When laser intensity is higher than10¹⁸W/cm²,the electron can immediately get enough energy and accordingly enter the relativistic optics regime,companying with several strong nonlinear physical phenomenon,such as laser relativistic self-focusing,laser wake field acceleration and high harmonic generation,etc.Recently,with the construction of ELI,SG-III and other next-generation of large-scale Petawatt?PW?laser facilities,the laser intensity is expected to break through10²³-²⁴W/cm²,which will extend the existing research to Strong field QED field.Un-der the strong field condition,electrons can be accelerated to extreme relativistic energy,and the radiation reaction can significantly influence the electron dynamics.This will trigger the fundamental QED processes,such as the generation of electrons,muons,?mesons and their corresponding antiparticles.Study of these processes may help us to reveal the structure of quantum vacuum.In addition,the research of novel ultra-short ultra-bright?-ray sources and dense electron-positron-pair plasmas can further promote the development of nuclear quantum optics and even find new particles beyond the stan-dard model.This opens up wide possibilities for people to study the extreme conditions of laser plasma interaction,companying with new opportunities and challenges.Recently,many researchers have devoted into this area of strong field QED and several prominent results are achieved.In this paper,we focus on the current research issue of ultra-short ultra-intense laser plasma interaction under the condition of strong field QED,and propose novel schemes to the generate ultra bright?-ray beams and dense electron-positron pairs.A brief intro-duction are presented as follows:Firstly,we proposed an all-optical scheme for ultra-bright?-ray emission and dense positron production with lasers at intensity of 10²33 W/cm².By irradiating two colliding elliptically-polarized lasers onto two diamondlike carbon foils,electrons in the focal re-gion of the foils are rapidly accelerated into extreme relativistical energy?GeV?by the radiation pressure of laser,which form the relativistical electron layers.The foils reach the threshold of the relativistically induced transparency before their colliding,and lasers in each sides penetrate the foil and subsequently collide with the other side of electrons.The symmetric configuration enables efficient nonlinear Compton scattering and results in ultra-bright?-ray emission with an extreme brightness of_?10²⁵photons/s/mm²/mrad²/0.1%BW at 15 MeV and intensity of 5×10²³W/cm².Our three dimensional simulation with quantum-electrodynamics incorporated shows that a dense positron source with maximal number density of 2.5×10²²cm-³and flux of 1.6×10¹⁰is achieved.Collective effects of such dense pairs plasmas may be triggered,offering a window on investigating laboratary astrophysics at next generation of PW laser facilities.Secondly,when considering the limits of the former scheme,such as the poor di-vergence of the radiation source and inconvenient guidance of the positron beams,we next propose a novel scheme to obtain a better beam quality.By irradiating a 10 PW linear polarised laser pulse with an intensity of 10²33 W/cm² onto a micro wire target,high energy attosecond electron bunches are tragged out and subsequently accelerated by laser ponderomotive force to GeV energy.These electron bunches collide with the counter-propagating laser pulse and intense nonlinear Compton scattering occurs,which obtains the?-ray flash with a peak brightness of 1.8×10²⁴photons/s/mm²/mrad²/0.1%BW.Concomitantly,these high energy photons propagate with low divergence and trigger the multi-photon Breit-Wheeler process.Dense attosecond positron bunches are gener-ated.The simulation results show that the positron flux is up to 1×10⁹and energy density is as high as 10¹77 J/m³ magnitude.Such ultra-bright?-ray flashes and attosecond positron bunches with a compact beam quality may have potential applications in fundamental physics,strong field ultra-fast physics and laboratory astrophysics.