Emission spectroscopy of expanding laser-induced gaseous hydrogen–nitrogen plasma

Abstract

Microplasma is generated in an ultra-high-pure H and N gas mixture with a Nd:YAG laser device that is operated at the fundamental wavelength of 1064 nm. The gas mixture ratio of H and N is 9 to 1 at a pressure of 1.21 ± 0.03 10 Pa inside a chamber. A Czerny-Turner-type spectrometer and an intensified charge-coupled device are utilized for the recording of plasma emission spectra. The line-of-sight measurements are Abel inverted to determine the radial distributions of electron number density and temperature. Recently derived empirical formulas are utilized for the extraction of values for electron density. The Boltzmann plot and line-to-continuum methods are implemented for the diagnostic of electron excitation temperature. The expansion speed of the plasma kernel maximum electron temperature amounts to 1 km/s at a time delay of 300 ns. The microplasma, initiated by focusing 14 ns, 140 mJ pulses, can be described by an isentropic expansion model.

Temporally and Spatially Resolved Emission Spectroscopy of Hydrogen, Cyanide and Carbon in Laser-Induced Plasma

“…Figure 6 displays the results. Analogous to recently reported hydrogen nitrogen gaseous mixtures [30], the CN signals are weaker at the center and indicate a slightly lower temperature than at 0.85 mm. There appears to be residual interference from an atomic line at 386.2 nm that indicates the carbon line at the 193.09-nm line [20,21], measured in second order.…”

Time-Resolved Emission Spectroscopy of Atomic and Molecular Species in Laser-Induced Plasma

“…Figure 6 displays the results and it shows a comparison of computed and of measured spectra 23,24 . Similar to recently reported hydrogen nitrogen gas mixtures 25 , the CN signals are weaker at the center and indicate a slightly lower temperature than for the 0.85 mm position. There appears to be residual interference from an atomic line at 386.2 nm that likely indicates the carbon line at 193.09 nm line measured in second order.…”

Temporally and Spatially Resolved Emission Spectroscopy of Cyanide, Hydrogen and Carbon in Laser-Induced Plasma

“…Figure 6 displays the results and it shows a comparison of computed and of measured spectra [28,29]. Analogous to recently reported hydrogen nitrogen gaseous mixtures [30], the CN signals are weaker at the center and indicate a slightly lower temperature than for the 0.85 mm position. There appears to be residual interference from an atomic line at 386.2 nm that indicates the carbon line at 193.09-nm line [20,21], measured in second order.…”