All-optical bright γ-ray and dense positron source by laser driven plasmas-filled cone.

An all-optical scheme for bright γ-rays and dense ee pair source is proposed by irradiating a 10 W/cm laser onto a near-critical-density plasmas filled Al cone. Two-dimensional (2D) QED particle-in-cell (PIC) simulations show that, a dense electron bunch is confined in the laser field due to the radiation reaction and the trapped electrons oscillate transversely, emitting bright γ-rays forward in two ways: (1) nonlinear Compton scattering due to oscillation of electrons in the laser field, and (2) Compton backwardscattering resulting from the bunch colliding with the reflected laser by the cone tip. Finally, the multi-photon Breit-Wheeler process is initiated, producing abundant ee pairs with a density of ∼ 10m. The scheme is further demonstrated by full 3D PIC simulations, which indicates a positron number up to 2 × 10. This compact γ-rays and ee pair source may have many potential applications, such as the laboratory study of astrophysics and nuclear physics.