近日，德国德累斯顿-罗森多夫亥姆霍兹中心的Tim Ziegler及其研究团队取得一项新进展。经过不懈努力，他们产生了源于自级联加速机制的激光驱动高能质子束。相关研究成果已于2024年5月13日在国际知名学术期刊《自然—物理学》上发表。

该研究团队借助重复拍瓦激光器的超短激光脉冲照射固体密度塑料箔靶，成功产生了能量高达150MeV的光谱分离高能质子束。在过程中，前置激光先加热靶材，使得主脉冲到达时靶材呈现相对论性感应透明状态。随后，激光峰值穿透原本不透明的靶材，并通过一系列复杂机制触发质子加速，这一过程得到了三维细胞内粒子模拟的验证。靶材的透明度变化可作为高性能区域的识别标志，为自动化激光和靶材优化提供了理想的反馈参数，有望显著提升未来等离子体加速器的稳定性。

据悉，激光驱动的离子加速器可以提供高能量、高峰值的电流束，作为传统加速器的一种紧凑型替代品，它们正吸引着人们的关注。然而，对于激光驱动的离子加速器来说，实现足够高的能级以适合放射治疗等应用仍然是一个挑战。

附：英文原文

Title: Laser-driven high-energy proton beams from cascaded acceleration regimes

Author: Ziegler, Tim, Gthel, Ilja, Assenbaum, Stefan, Bernert, Constantin, Brack, Florian-Emanuel, Cowan, Thomas E., Dover, Nicholas P., Gaus, Lennart, Kluge, Thomas, Kraft, Stephan, Kroll, Florian, Metzkes-Ng, Josefine, Nishiuchi, Mamiko, Prencipe, Irene, Pschel, Thomas, Rehwald, Martin, Reimold, Marvin, Schlenvoigt, Hans-Peter, Umlandt, Marvin E. P., Vescovi, Milenko, Schramm, Ulrich, Zeil, Karl

Issue&Volume: 2024-05-13

Abstract: Laser-driven ion accelerators can deliver high-energy, high-peak current beams and are thus attracting attention as a compact alternative to conventional accelerators. However, achieving sufficiently high energy levels suitable for applications such as radiation therapy remains a challenge for laser-driven ion accelerators. Here we generate proton beams with a spectrally separated high-energy component of up to 150MeV by irradiating solid-density plastic foil targets with ultrashort laser pulses from a repetitive petawatt laser. The preceding laser light heats the target, leading to the onset of relativistically induced transparency upon main pulse arrival. The laser peak then penetrates the initially opaque target and triggers proton acceleration through a cascade of different mechanisms, as revealed by three-dimensional particle-in-cell simulations. The transparency of the target can be used to identify the high-performance domain, making it a suitable feedback parameter for automated laser and target optimization to enhance stability of plasma accelerators in the future.

DOI: 10.1038/s41567-024-02505-0

Source: https://www.nature.com/articles/s41567-024-02505-0