Journal of Experimental and Theoretical Physics

, Volume 84, Issue 4, pp 703–715

Mechanisms of resonant laser ionization

  • A. G. Leonov
  • D. I. Chekhov
  • A. N. Starostin
Plasma, Gases

DOI: 10.1134/1.558204

Cite this article as:
Leonov, A.G., Chekhov, D.I. & Starostin, A.N. J. Exp. Theor. Phys. (1997) 84: 703. doi:10.1134/1.558204

Abstract

An experimental investigation and numerical simulation of resonant laser breakdown are performed. As a result, quantitative agreement between the experimental data on the parameters of a dense resonant plasma (the electron density and the electron temperature) and the results of calculations in the range of detunings of the laser radiation from resonance Δλ>2–2.5 nm, in which the spatial instability of the intense resonant laser beam and the absorption of radiation are minimal, is obtained for the first time. It is shown that the previously proposed mechanism of resonant breakdown associated with laser-induced associative ionization introduces only a small correction to the final extent of ionization of the resonant plasma and scarcely alters its temperature. The influence of quantum stimulated inverse bremsstrahlung processes, which are usually described as collisions of the second kind in the resonance case, on the energy gain by electrons is analyzed for the first time in reference to specific experimental findings. The numerical calculations show that at detunings of the order of the Rabi frequency, the mechanism by which electrons gain energy through the resonant system does not reduce to collisions of the second kind and can significantly increase the density of the resonant plasma. However, in this range of detunings the laser beam is still strongly perturbed by instability processes, precluding a proper comparison of the theory with experiment. At large Δλ the classical and quantum cases differ from one another only slightly, and the values of Ne calculated for both mechanisms lie within the measurement error.

Copyright information

© American Institute of Physics 1997

Authors and Affiliations

  • A. G. Leonov
    • 1
  • D. I. Chekhov
    • 1
  • A. N. Starostin
    • 2
  1. 1.Moscow Physicotechnical InstituteDolgoprudnyi, Moscow RegionRussia
  2. 2.Troitsk Institute of Innovative and Thermonuclear ResearchTroitsk, Moscow RegionRussia