Open AccessEnhancement of ion generation in low-contrast laser-foil interactions by defocusing
Author(s) -
M. Xu,
Yutong Li,
Feng Liu,
Yi Zhang,
Lin Xiao-Xuan,
Shoujun Wang,
Meng Li-Min,
Zhaohua Wang,
Jun Zheng,
Zheng-Ming Sheng,
Zhiyi Wei,
Yingjun Li,
Jie Zhang
Publication year - 2011
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.60.045204
Subject(s) - laser , proton , laser beam quality , femtosecond , foil method , optics , acceleration , atomic physics , ion , electron , physics , beam (structure) , electric field , collimated light , kinetic energy , materials science , laser beams , nuclear physics , quantum mechanics , composite material , classical mechanics
The characteristics of proton beams generated from ultra-intense laser-foil interactions under varied focal offsets are experimentally studied on XL-Ⅱ laser facility.The experimental results show that when strong femtosecond prepulses are presented before the main pulse, the conversion efficiency from the laser energy to the protons is enhanced by 3 orders of magnitude with effective improvement of the beam collimation by properly defocusing the laser pulses. The depression of the prepulse effect on the proton acceleration is believed to be one of the main reasons for the significant optimization. Besides, the particle-in-cell (PIC) simulation results indicate that the population of moderate energy electrons increases under large focal offsets, which in turn effectively improves the acceleration electric field and the beam quality.