Scattering of CO2 laser beam by a plasma of air breakdown at pressures of 1–300 torr

Meshalkin, E. A.

doi:10.1134/1.1395120

Cited by 1 publication

(1 citation statement)

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“…First, as stated above, the experimental results include the effects of eventual scattering losses, which are not incorporated in the air LIB model. The scattering of incident radiation by a laser-induced plasma has been extensively investigated in the literature for different ranges of laser power densities, wavelengths, and for different mixtures [90][91][92][93][94]. For the cases under investigation, the integrated scattered energy due to Rayleigh, Mie, and Thomson scattering combined together is expected to be a few percent of the incident energy, with scattering losses measured up to ≈10% for some operating mode (e.g.…”

Section: Parametric Study On Input Energy Wavelengthmentioning

confidence: 99%

Laser-induced non-equilibrium plasma kernel dynamics

Alberti

Munafò

Koll

et al. 2019

J. Phys. D: Appl. Phys.

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A non-equilibrium model for laser generated plasmas is validated and used to investigate plasma kernel dynamics. Breakdowns in quiescent air at different ambient conditions (e.g. pressure) for different laser parameters (e.g. power density and beam wavelength) are considered. The hydrodynamics is described based on the chemically reactive Navier–Stokes equations where non-equilibrium effects are accounted for using a three-temperature model. Laser-plasma interactions over nano-second time-scales are modeled with a radiative transfer equation (RTE), including both multiphoton ionization (MPI) and inverse Bremsstrahlung (IB). Validation is conducted by comparing absorbed energy and plasma emission with the corresponding experimental measurements, and by observations of the structure of the breakdown. The laser generated plasma exhibits a two-lobe structure, developing both in the forward and backward directions. An analysis of the dynamics suggests that the kernel evolution results from a radiation-driven wave that is: (i) triggered by MPI, (ii) sustained by energy deposition in IB interactions, which compensates for the energy lost by free-electrons in ionizing collisions, and (iii) guided by both MPI and ionization by electron impact (IE).

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