Measurement and analysis of K-shell emission spectra of Si nanowire arrays irradiated at relativistic intensities

Relativistic laser-matter interaction has been an important platform for studying the extreme properties of high-energy-density(HED) plasmas [1]. Recently, nanowire array targets have attracted much interest due to their high optical absorption [2]. They are considered a unique means of efficient x-ray source development and accessing the well-defined HED regime [3,4]. Here we present the measurement and analysis of K-shell emission spectra (1.70-2.04 keV) of Si nanowire arrays irradiated by 150 TW Ti:sapphire laser pulses at the CoReLS. A peak laser intensity is above 10²⁰ W/cm². Ly-a, He-a, and their satellites emissions are measured for various nanowire lengths and laser pre-pulse conditions. We also calculate Si K-shell emission spectra using a collisional radiative code FLYCHK [5] for various plasma parameters. Detailed modeling and comparison with experimental data will be presented.

References

[1] Ditmire, T., et al., Radiation Physics and Chemistry, 70, 535-552 (2004).

[2] Kulcsar, G., et al., Physical review letters 84, 5149 (2000).

[3] Purvis, Michael A., et al., Nature photonics, 7, 796-800 (2013).

[4] Bargsten, Clayton, et al., Science advances 3, e1601558 (2017).

[5] Chung, H-K., et al., High energy density physics 1, 3-12 (2005).