标题： 使用400 GeV/c质子生成超密集对束 显示英文标题

标题： Generating ultra-dense pair beams using 400 GeV/c protons

摘要： 一种之前未被探索的实验方案被提出，用于利用HiRadMat和CERN的AWAKE设施提供的400 GeV/c质子生成低发散、超密集、相对论性电子-正电子束。初步的蒙特卡罗和粒子模拟表明，生成包含$10^{13}-10^{14}$个电子-正电子对的束流是可能的，其密度足够高以驱动无碰撞束-等离子体不稳定性，这些不稳定性预计将在磁场生成及相关相对论天体物理现象的辐射特征中发挥重要作用。这些电子-正电子束是准中性的，在所有维度上的尺寸都超过几个皮层深度，从而首次能够检查横向和纵向不稳定性模式之间的竞争对磁场增长的影响。此外，所提出的方案允许控制束流中强子与电子-正电子对的相对密度，使得可以探索不同天体物理环境的参数空间。 显示英文摘要

摘要： A previously unexplored experimental scheme is presented for generating low-divergence, ultra-dense, relativistic, electron-positron beams using 400 GeV/c protons available at facilities such as HiRadMat and AWAKE at CERN. Preliminary Monte-Carlo and Particle-in-cell simulations demonstrate the possibility of generating beams containing $10^{13}-10^{14}$ electron-positron pairs at sufficiently high densities to drive collisionless beam-plasma instabilities, which are expected to play an important role in magnetic field generation and the related radiation signatures of relativistic astrophysical phenomena. The pair beams are quasi-neutral, with size exceeding several skin-depths in all dimensions, allowing for the first time the examination of the effect of competition between transverse and longitudinal instability modes on the growth of magnetic fields. Furthermore, the presented scheme allows for the possibility of controlling the relative density of hadrons to electron-positron pairs in the beam, making it possible to explore the parameter spaces for different astrophysical environments.