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Collective Thomson scattering (TS) is a powerful technique to accurately diagnose the parameters of laser-produced plasmas. However, when the scattering parameter α, which is inverse to the product of electron Debye length and wavenumber of plasma fluctuations, is significantly larger than 1, which of the conditions is easily satisfied in the experiment, the accuracy of electron density measurement is usually poor just with the single-wavenumber ion-acoustic wave feature of the TS spectrum. This situation can be greatly improved in the imaging TS experiment because the signal intensity is proportional to electron density. A novel algorithm is developed and validated for the data analysis of imaging TS through the combination of signal intensity and spectral profile. The results show that we can obtain the electron density with high confidence, as well as other plasma parameters like electron and ion temperatures. [ABSTRACT FROM AUTHOR]

A novel high-speed multi-frame photographic system is presented in this paper. The system demonstrates exceptional compactness and flexibility, requiring only the introduction of a cavity comprising multiple beam-splitters in the optical path to enable multi-frame imaging of sub-nanosecond events. The number and temporal delay of frames can be easily adjusted by adjusting the distance and angle between beam-splitters. These capabilities are demonstrated by observing the laser ablation process, highlighting the great potential for application in capturing ultrafast time-evolving events such as optical breakdown, the evolution of laser-produced plasmas, and the propagation of shock waves. [ABSTRACT FROM AUTHOR]

In this article, we present experiments measuring the electron density of a blown-off aluminum plasma created by a 2 ω (532 nm) laser using dual-angle Thomson scattering diagnosis. By fitting two ion-acoustic-wave feature spectra collected from two angles simultaneously, in a typical shot, the electron density obtained 400 μ m in front of the target as given by Thomson scattering diagnosis was (5.9 ± 0.6) × 10 18 cm − 3 , which is 35% higher than the average result of (4.4 ± 0.7) × 10 18 cm − 3 as measured by digital holography diagnosis. The distribution of the electron density along the laser axis from 400 μ m to 700 μ m as given by dual-angle Thomson scattering was broadly consistent with that obtained from digital holography diagnosis. At a location of 250 μ m in front of the target, a unique set of plasma parameters cannot be obtained by dual-angle Thomson scattering diagnosis. This may be a result of the steep density gradient visible in the hologram in this region. Dual-angle Thomson scattering diagnosis can provide a good estimation of the electron density in plasma parameter regimes similar to those in these experiments, in which the scattering parameter α < 2. This technique may be useful for small laser facilities that cannot afford a second probe laser with a different wavelength and for measuring electron density with 4 ω Thomson scattering on large laser facilities. This article presents several factors that need to be considered when employing this method. [ABSTRACT FROM AUTHOR]