强激光与粒子束
2022, 34(4): 049002
Author Affiliations
Abstract
1 Lawrence Berkeley National Laboratory, Berkeley, CA, USA
2 Keldysh Institute of Applied Mathematics RAS, Moscow, Russia
3 ELI Beamlines, Dolní Břežany, Czech Republic
We measured the parameter reproducibility and radial electron density profile of capillary discharge waveguides with diameters of 650 $\mathrm{\mu} \mathrm{m}$ to 2 mm and lengths of 9 to 40 cm. To the best of the authors’ knowledge, 40 cm is the longest discharge capillary plasma waveguide to date. This length is important for $\ge$10 GeV electron energy gain in a single laser-driven plasma wakefield acceleration stage. Evaluation of waveguide parameter variations showed that their focusing strength was stable and reproducible to $<0.2$% and their average on-axis plasma electron density to $<1$%. These variations explain only a small fraction of laser-driven plasma wakefield acceleration electron bunch variations observed in experiments to date. Measurements of laser pulse centroid oscillations revealed that the radial channel profile rises faster than parabolic and is in excellent agreement with magnetohydrodynamic simulation results. We show that the effects of non-parabolic contributions on Gaussian pulse propagation were negligible when the pulse was approximately matched to the channel. However, they affected pulse propagation for a non-matched configuration in which the waveguide was used as a plasma telescope to change the focused laser pulse spot size.
capillary plasma waveguide laser-driven plasma wakefield acceleration plasma telescope matched laser guiding High Power Laser Science and Engineering
2021, 9(2): 02000e17
1 国防科学技术大学 理学院, 长沙 410073
2 中国卫星海上测控部 技术部, 江苏 江阴 214431
3 中国工程物理研究院 激光聚变研究中心, 四川 绵阳621900
4 国防科学技术大学 计算机学院, 长沙 410073
用2D3V粒子模拟程序研究了高能质子束驱动的尾波场加速电子的方案, 及其在此方案中应用背景等离子体密度的跃变致使等离子体电子自注入加速相区的可能性。粒子模拟结果显示: 密度跃变实现了电子的自注入, 并且捕获的电子束处于加速相位, 等离子体尾波场纵向电场对捕获的电子束起箍缩作用; 捕获的电子束随着传输, 表现为窄能谱分布; 同时随着密度跃变大小的增大, 可以增加等离子体电子的捕获。
质子束 粒子模拟 等离子体尾波加速 密度跃变 电子捕获 proton beam PIC simulation plasma wakefield acceleration density transition electron trapping