Two-dimensional Thomson scattering in high-repetition-rate laser-plasma experiments

H. Zhang; J. J. Pilgram; C. G. Constantin; L. Rovige; P. V. Heuer; S. Ghazaryan; M. Kaloyan; R. S. Dorst; D. B. Schaeffer; C. Niemann

doi:10.3390/instruments7030025

arXiv · 2305.07843

Two-dimensional Thomson scattering in high-repetition-rate laser-plasma experiments

H. Zhang·J. J. Pilgram·C. G. Constantin·L. Rovige·P. V. Heuer·S. Ghazaryan·M. Kaloyan·R. S. Dorst·D. B. Schaeffer·C. Niemann

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Abstract

We present the first two-dimensional (2D) optical Thomson scattering measurements of electron density and temperature in laser-produced plasmas. The novel instrument directly measures $n_e(x,y)$ and $T_e(x,y)$ in two dimensions over large spatial regions (cm$^2$) with sub-mm spatial resolution, by automatically translating the scattering volume while the plasma is produced repeatedly by irradiating a solid target with a high-repetition-rate laser beam (10 J, $\sim$10$^{12}$ W/cm$^2$, 1 Hz). In this paper, we describe the design and auto-alignment of the instrument, and the computerized fitting algorithm of the spectral distribution function to large data-sets of measured scattering spectra, as they transition from the collective to the non-collective regime with distance from the target. As an example, we present 2D scattering measurements in laser driven shock waves in ambient nitrogen gas at a pressure of 95 mTorr.

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H. Zhang, J. J. Pilgram, C. G. Constantin, L. Rovige, P. V. Heuer, S. Ghazaryan, M. Kaloyan, R. S. Dorst, D. B. Schaeffer, C. Niemann. 2023-05-13. Two-dimensional Thomson scattering in high-repetition-rate laser-plasma experiments. https://doi.org/10.3390/instruments7030025

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