摘要
High-energy positrons and bright g-ray sources are of great importance both in fundamental research and for practical applications.However,collimated GeV electron–positron pair jets and g-ray flashes are still rarely produced in the laboratory.Here,we demonstrate that by irradiating a near-critical-density plasma channel with two 10 PW-scale laser pulses,highly directional GeV electron–positron pairs and bright g-ray beams can be efficiently generated.Three-dimensional particle-incell simulations show the formation of GeV positron jets with high density(8×10^(21)=cm^(3)),attosecond duration(400 as),and a divergence angle of 14°.Additionally,ultrabright[2×10^(25) photons s^(-1)1 mm^(-2) mrad^(-2) (0.1%bandwidth_(-1)]collimated attosecond(370 as)g-ray flashes with a laser energy conversion efficiency of 5.6%are emitted.These features show the significant advantage of using a plasma channel as compared with a uniformplasma and thus open up new possibilities for a wide variety of applications.
基金
supported in part by the National Key Research and Development Program of China(Grant No.2018YFA0404802)
the NSFC(Grant Nos.11721091,11774227,11622547,and 11655002)
the Hunan Provincial Natural Science Foundation of China(Grant No.2017JJ1003)
a Leverhulme Trust Grant at the University of Strathclyde。
