Influence of the macrotransport processes in gases on the change in the hydrodynamic parameters in the presence of a resonance radiation pulse

Modeling of the dynamics of the change in the index of refraction during resonance interaction of radiation with vibrational-rotational transitions

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It is well known that resonance absorption of radiation by a gas can lead to excitation of molecular internal degrees of freedom, and this determines, to a significant degree, the nonlinear response of the medium. Hydrodynamic effects have been analyzed primarily within the model of a nonviscous thermally nonconducting gas, neglecting the influence of diffusion and heat conduction, which in a vibrationally nonequilibrium gas depends significantly on the degree of excitation and can significantly influence the behavior of the concentrations of the mixture components even over times shorter than the characteristic times of these processes [8]. The imaginary part is associated with the absorption coefficient tq, and the real part is associated with the index of refraction n. A change of n in the beam channel causes the light rays to be deflected from the initial direction and determines, to a significant degree, the character of laser propagation in a nonlinear medium [1].

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“…Hydrodynamic effects have been analyzed primarily within the model of a nonviscous thermally nonconducting gas, neglecting the influence of diffusion and heat conduction, which in a vibrationally nonequilibrium gas depends significantly on the degree of excitation and can significantly influence the behavior of the concentrations of the mixture components even over times shorter than the characteristic times of these processes [8]. Hydrodynamic effects have been analyzed primarily within the model of a nonviscous thermally nonconducting gas, neglecting the influence of diffusion and heat conduction, which in a vibrationally nonequilibrium gas depends significantly on the degree of excitation and can significantly influence the behavior of the concentrations of the mixture components even over times shorter than the characteristic times of these processes [8].…”

“…According to [8,14] this system has the following form: Here the relaxation of the energies in the modes v 1 and v 2 can be combined, making the assumption that the 10~ and 0200 states of the CO 2 molecule are in exact resonance 0av t = 2hv2). (2) that in order to calculate 6n it is necessary to know how N i and Tj behave.…”

“…In order to determine the changes in N i and Tj under the action of resonance radiation on a medium at rest, we shall employ the system of Navier--Stokes equations for a vibrationally nonequilibrium gas. Assuming, as in [8], that the relations presented also hold for the diffusion coefficients in a binary gas, we obtain 17) describing the vibrational kinetics for the mixture CO2--N 2 was solved numerically by the method developed in [8]. In our investigation this combined mode corresponds to v k, the asymmetric vibrations of CO 2 (v 3) correspond to ~,q, and the vibrations N 2 (v 4) correspond to v s. We note that the form of the right-hand side of Eq.…”