This work communicates laser-plasma experiments in a gaseous mixture of hydrogen and nitrogen. Time-resolved spectroscopy measures the first four Balmer series hydrogen lines together with selected neutral and ionized nitrogen lines. Optical breakdown plasma is generated in a 1:1 hydrogen:nitrogen mixture at ambient temperature and 0.27-atm pressure. Time-resolved spectroscopy records emitted radiation with spatial resolution along the slit height for the Hα, Hβ, Hγ, and Hδ lines. For 13 selected time delays from 0.25 µs to 3.25 µs and 0.025 µ gate-widths, micro-plasma diagnostics is evaluated. Of interest are the peak-separation and width of Hδ and width of Hγ for electron densities in the range of 0.1 to 1.0×1017 cm-3, and comparisons with Hβ and Hα diagnostics. Integral inversions interrogate spatial distributions of the plasma expansion. Applications include laboratory and stellar astrophysics plasma diagnosis.
atomic and molecular spectroscopy; time-resolved spectroscopy; laser plasma; laser-induced optical breakdown; stellar astrophysics spectra; white dwarf stars; hydrogen
PHYSICAL SCIENCES, Fluids & Plasmas
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