Zhou Shiyu, Hua Jianfei, An Weiming, Mori Warren B, Joshi Chan, Gao Jie, Lu Wei
Department of Engineering Physics, Tsinghua University, Beijing 100084, China.
Beijing Normal University, Beijing 100875, China.
Phys Rev Lett. 2021 Oct 22;127(17):174801. doi: 10.1103/PhysRevLett.127.174801.
Plasma wakefield acceleration in the blowout regime is particularly promising for high-energy acceleration of electron beams because of its potential to simultaneously provide large acceleration gradients and high energy transfer efficiency while maintaining excellent beam quality. However, no equivalent regime for positron acceleration in plasma wakes has been discovered to date. We show that after a short propagation distance, an asymmetric electron beam drives a stable wakefield in a hollow plasma channel that can be both accelerating and focusing for a positron beam. A high charge positron bunch placed at a suitable distance behind the drive bunch can beam-load or flatten the longitudinal wakefield and enhance the transverse focusing force, leading to high efficiency and narrow energy spread acceleration of the positrons. Three-dimensional quasistatic particle-in-cell simulations show that an over 30% energy extraction efficiency from the wake to the positrons and a 1% level energy spread can be simultaneously obtained. Further optimization is feasible.
爆轰模式下的等离子体尾场加速对于电子束的高能加速特别有前景，因为它有潜力在保持优异束流品质的同时，提供大的加速梯度和高的能量转移效率。然而，迄今为止尚未发现等离子体尾流中用于正电子加速的等效模式。我们表明，在短传播距离后，非对称电子束在空心等离子体通道中驱动稳定的尾场，该尾场对正电子束既可以加速又可以聚焦。放置在驱动束后面适当距离处的高电荷正电子束团可以对纵向尾场进行束加载或使其平坦化，并增强横向聚焦力，从而实现正电子的高效率和窄能量分散加速。三维准静态粒子模拟表明，可以同时实现从尾场到正电子超过30%的能量提取效率和1%水平的能量分散。进一步优化是可行的。
