基于横向梯度波荡器的阿秒级电子束压缩方案模拟

Liu Yinghan; Gu Duan

doi:10.11884/HPLPB202638.250413

基于横向梯度波荡器的阿秒级电子束压缩方案模拟

doi: 10.11884/HPLPB202638.250413

刘颖颔^{1, 3,},
谷端^2, ,

1.
中国科学院上海应用物理研究所，上海 201800
2.
中国科学院上海高等研究院，上海 201210
3.
中国科学院大学，北京 100049

详细信息

中图分类号: TL53
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- 文章访问数: 19
- HTML全文浏览量: 13
- PDF下载量: 2
- 被引次数: 0
出版历程
- 收稿日期: 2025-11-19
- 修回日期: 2026-04-15
- 录用日期: 2026-04-13
- 网络出版日期: 2026-05-06

Attosecond electron bunch compression scheme based on transverse gradient undulator

Liu Yinghan^{1, 3
,},
Gu Duan^{2
, ,}

1.
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
2.
Shanghai Advance Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
3.
University of Chinese Academy of Sciences, Beijing 100049, China

Funds: Supported by Shanghai Action Plan for Science, Technology and Innovation (24JD1402800), National Key Research and Development Program of China (2024YFA1612201), National Natural Science Foundation of China (12575162)

More Information

Author Bio:
Liu Yinghan, liuyinghan@sinap.ac.cn

Corresponding author: Gu Duan, gud@sari.ac.cn

摘要

摘要: 亚飞秒电子束在推动超快研究方面具有巨大潜力，包括超快电子衍射和自由电子激光。然而传统压缩技术本质上受限于切片能散，难以产生亚飞秒电子束。本文提出基于横向梯度波荡器（TGU）的新压缩方案，利用TGU抑制切片能散，从而突破压缩极限。数值模拟表明，该方案可将电子束从50 fs压缩至1 fs以下。同时还讨论了电子枪中电场的相位和峰值电场抖动对束长压缩结果造成的影响，以及抑制该影响的手段。
- 阿秒电子束 /
- 电子束压缩 /
- 横向梯度波荡器 /
- 切片能散 /
- 超快电子衍射
Abstract: Background
Sub-femtosecond electron beams offer enormous promise for furthering ultrafast research, including ultrafast electron diffraction and free-electron lasers. However, traditional compression techniques are essentially constrained by slice energy spread and cannot stably produce sub-femtosecond electron beams.
Purpose
This work proposes a unique compression strategy based on a Transverse Gradient Undulator (TGU). The slice energy spread is actively reduced by taking advantage of the link between transverse position and energy modulation in the TGU, hence breaking the compression limit.
Methods
Theoretical proof has been provided of the suppression effect of TGU on slice energy spread, with confirmation of the relevant parameters influencing this effect. A complete compression beamline has been designed, and numerical simulations conducted.
Results
Numerical simulations show that the proposed approach may compress the electron beam from 50 fs to less than 1 fs, with a compression factor over 52.09. Although phase jitter in the electron gun’s electric field affects the final compression pulse length, adjusting the modulation laser parameters of the TGU can effectively improve the compression results.
Conclusions
This study confirms that the TGU with flexible tunability and suppression of slice energy dispersion can be explored to be applied in ultrafast science research.
- attosecond electron bunch /
- bunch compression /
- transverse gradient undulator /
- slice energy spread /
- ultrafast electron diffraction

HTML全文

Figure 1. Schematic of a TGU^[25]

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Figure 2. (a)Schematic of TGU based bunch compression, (b) electron beam longitudinal phase space and current density profile evolutions

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Figure 3. Suppression effect of TGU on slice energy spread

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Figure 4. Statistical results of the pulse width compression jitter with errors

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Figure 5. Electronic longitudinal phase space at the TGU exit and beamline exit and current density profile at beamline exit with error of the electron gun

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Table 1. The main parameters

Electric field amplitude	Launch phase	Output energy	Beam charge	Number of electrons	Radius (rms)	Initial pulse duration (rms)
175 MV/m	40°	3.793 MeV	20 fC	20000	50 μm	50 fs
θ1 of D1,D2	LB1 of D1,D2	η of dogleg	transverse gradient α of TGU	dimensionless parameter K0 of TGU	laser wavelength	laser peak power
18°	0.1 m	0.05668 m	55 m⁻¹	1.5	1 mm	6.85 MW
laser phase	geometric strength of Q1	geometric strength of Q2	θ2 of D3	LB2 of D3
−32 °	140 m⁻²	−49.1 m⁻²	5 °	0.1 m

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