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arXiv · 2609.33285

In-situ Generation of Polarized Attosecond Positron Bunches via Radiation-Wakefield Induced Two-Photon Pairs

Zhen-Ke Dou·Qian Zhao·Hao-Tian Wang·Feng Wan·Jian-Xing Li
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Abstract

High-energy, dense, spin-polarized positron beams with attosecond duration are highly desirable for advanced accelerator physics, laboratory astrophysics, and ultrafast matter-antimatter studies, yet remain beyond the capability of conventional source and injection-based plasma-acceleration schemes. We propose an integrated in-situ method for production, trapping, and accelerating polarized attosecond positron bunches in a single plasma stage. An ultraintense hollow laser propagating in a plasma channel drives a radiative wakefield, where longitudinally injected electrons emit a dense MeV gamma-ray bath through nonlinear Compton scattering. Subsequent photon-photon collisions induce linear Breit-Wheeler pair production, while linear and nonlinear radiative processes mediate polarization transfer to the produced positrons. Spin-resolved QED particle-in-cell simulations indicate that the laser-modulated wakefield naturally captures positrons born in the frontier bubble wake, forming collimated bunch trains with hundred-attosecond duration, GeV-level energies, densities up to 10^17 cm^-3, and maintained polarization. Parameter scans demonstrate robustness against variations of laser intensity and plasma-channel density. This single-shot, source-free approach simultaneously addresses positron production, polarization, temporal compression, and plasma injection, offering a compact route toward polarized attosecond antimatter beams.

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Zhen-Ke Dou, Qian Zhao, Hao-Tian Wang, Feng Wan, Jian-Xing Li. 2026-09-27. In-situ Generation of Polarized Attosecond Positron Bunches via Radiation-Wakefield Induced Two-Photon Pairs. https://arxiv.org/abs/2609.33285

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