Synchronous post-acceleration of laser-driven protons in helical coil targets by controlling the current dispersion
Post-acceleration of protons in helical coil targets driven by intense, ultrashort laser pulses can enhance ion energy by utilizing the transient current from the targets’ self-discharge. The acceleration length of protons can exceed a few millimeters, and the acceleration gradient is of the order of GeV/m. How to ensure the synchronization between the accelerating electric field and the protons is a crucial problem for efficient post-acceleration. In this paper, we study how the electric field mismatch induced by current dispersion affects the synchronous acceleration of protons. We propose a scheme using a two-stage helical coil to control the current dispersion. With optimized parameters, the energy gain of protons is increased by four times. Proton energy is expected to reach 45 MeV using a hundreds-of-terawatts laser, or more than 100 MeV using a petawatt laser, by controlling the current dispersion.
Zhipeng Liu, Zhusong Mei, Defeng Kong, Zhuo Pan, Shirui Xu, Ying Gao, Yinren Shou, Pengjie Wang, Zhengxuan Cao, Yulan Liang, Ziyang Peng, Jiarui Zhao, Shiyou Chen, Tan Song, Xun Chen, Tianqi Xu, Xueqing Yan, Wenjun Ma. Synchronous post-acceleration of laser-driven protons in helical coil targets by controlling the current dispersion[J]. High Power Laser Science and Engineering, 2023, 11(4): 04000e51.