Powerful lasers interacting with solid targets can generate intense electromagnetic pulses (EMPs). In this study, EMPs produced by a pulsed laser (1 ps, 100 J) shooting at CH targets doped with different titanium (Ti) contents at the XG-III laser facility are measured and analyzed. The results demonstrate that the intensity of EMPs first increases with Ti doping content from 1% to 7% and then decreases. The electron spectra show that EMP emission is closely related to the hot electrons ejected from the target surface, which is confirmed by an analysis based on the target–holder–ground equivalent antenna model. The conclusions of this study provide a new approach to achieve tunable EMP radiation by adjusting the metal content of solid targets, and will also help in understanding the mechanism of EMP generation and ejection of hot electrons during laser coupling with targets.
Ultra-short untraintense laser interacting with solid targets can produce significant electromagnetic pulses (EMPs), which are strongly pertinent to laser and target parameters. In this study, EMPs' generation due to pulsed laser (30 fs, 6×1019 W/cm2) irradiating aluminum foils are recorded and analyzed. The experimental results indicate a pre-ablation pulse (200 ps, 1×1012 W/cm2) that tends to enhance the electromagnetic emission inside the target chamber and the diagnostic cavity. The largest EMP signal is obtained when the pre-ablation pulse is incident on the target at 100 ps prior to the main laser beam. Meanwhile, the frequencies of EMPs are broadened up to 2 GHz in the diagnostic cavity in the 100 ps delayed case, indicating that EMPs with higher frequencies can be generated if the most energetic electrons are accelerated. The simulating results verify expansion of the pre-plasmas induced by the pre-ablation laser, which is beneficial to lift both the energy and quantity of hot electrons escaping from the target, accounting for the ehancement of EMPs. The resulting conclusions offer a new avenue to generate intense EMPs, which can be potentially used in nondestructive examination, high-power microwave source, and energy transfer.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.