Creation and direct laser acceleration of positrons in a single stage

Relativistic positron beams are required for fundamental research in nonlinear strong field QED, plasma physics, and laboratory astrophysics. Positrons difficult to create manipulate due their short lifetime, energy gain is limited by the accelerator size conventional facilities. Alternative compact concepts plasmas becoming more mature electrons, but generation acceleration remain an outstanding challenge. Here, we propose a new setup where can generate, inject, accelerate them single stage during propagation of intense laser channel. The positrons created from laser-electron collision at 90\ifmmode^\circ\else\textdegree\fi{}, injection guiding made possible 800-nC electron beam loading which reverses sign background electrostatic field. We obtain 17-fC beam, with GeV-level central within 0.5 mm plasma.