We propose a novel laser-driven positron source with a microwire-embedded conical target, where the laser-plasma interaction is enhanced by the aligned microwires grown on the inner wall of a conical cavity. The conical target structure facilitates laser mode conversion from transverse to longitudinal field components, generating a spatially uniform longitudinal electric field that extends longitudinally over several micrometers. This electric field effectively accelerates electrons pulled from the microwires, significantly enhancing the energy and yield of electrons produced. Then, the electrons bombard a high-Z converter to generate high-energy high-yield positrons. By employing three-dimensional particle-in-cell and Monte Carlo simulation techniques, it was shown that a positron beam featuring a cutoff energy of 114 MeV and a yield of 2.67×1010 particles is generated by using a femtosecond laser with an intensity of 5.5×1020 W/cm2.
Jiang et al. (Sun,) studied this question.