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

Automated summary

Relativistic positron beams are essential for fundamental research in nonlinear strong field QED, plasma physics, and laboratory astrophysics. However, creating and manipulating positrons is challenging due to their short lifetime and limited energy gain in conventional accelerators. In this study, a new setup is proposed to generate, inject, and accelerate positrons during the propagation of an intense laser in a plasma channel. This setup involves a laser-electron collision at 90 degrees and utilizes an 800-nC electron beam loading to reverse the sign of the background electrostatic field, enabling injection and guidance of the positrons. The obtained positron beam has a charge of 17 fC and a central energy at the GeV level within 0.5 mm of plasma.