Enhanced electron injection in laser-driven bubble acceleration by ultra-intense laser irradiating foil-gas targets.

A scheme for enhancing the electron injection charge in a laser-driven bubble acceleration is proposed. In this scheme, a thin foil target is placed in front of a gas target. Upon interaction with an ultra-intense laser pulse, the foil emits electrons with large longitudinal momenta, allowing them to be trapped into the transmitted shaped laser-excited bubble in the gaseous plasma target. Twodimensional particle-in-cell simulation is used to demonstrate this scheme, and an electron beam with a total electron number of 4.21 × 10⁸ μm^-1 can be produced, which is twice the number of electrons produced without the foil. Such scheme may be widely used for applications that require high electron yields such as positron and gamma ray generation from relativistic electron beams interacting with solid targets. [ABSTRACT FROM AUTHOR]