辐射尾场诱导双光子对产生阿秒极化正电子束的原位生成

中文摘要 AI 辅助

高能、高密度、自旋极化的阿秒正电子束对于先进加速器物理、实验室天体物理以及超快物质-反物质研究极具吸引力，但传统源和基于注入的等离子体加速方案仍无法实现。我们提出了一种集成式原位方法，在单个等离子体阶段中实现极化阿秒正电子束的产生、捕获和加速。在等离子体通道中传播的超强空心激光驱动辐射尾场，纵向注入的电子通过非线性康普顿散射发射致密的MeV伽马射线浴。随后的光子-光子碰撞诱导线性Breit-Wheeler对产生，而线性和非线性辐射过程介导了向所产生的正电子的极化转移。自旋分辨QED粒子模拟表明，激光调制的尾场自然捕获在前沿泡尾迹中产生的正电子，形成具有百阿秒持续时间、GeV级能量、高达10^17 cm^-3密度并保持极化的准直束团列。参数扫描证明了对激光强度和等离子体通道密度变化的鲁棒性。这种单发、无源方法同时解决了正电子产生、极化、时间压缩和等离子体注入问题，为极化阿秒反物质束提供了一条紧凑路径。

英文摘要

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.

发表机构

• School of Physics, Xi’an Jiaotong University（西安交通大学物理学院）

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