Vol. 22, issue 11, article # 1

Zimakov V. P., Kuznetsov V. A., Kedrov A. Yu., Solov'yov N. G., Shemyakin A. N., Yakimov M. Yu. Laser beam refraction in a continuous optical discharge plasma in a gas flow under atmospheric pressure. // Optika Atmosfery i Okeana. 2009. V. 22. No. 11. P. 1023-1028 [in Russian].
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Abstract:

The results of the experimental investigation of the sustaining laser beam refraction in a continuous optical discharge (COD) plasma, stabilized in a focused (f/4.4) laser beam and coaxial gas flow, are presented for the first time. Spatial distributions of the intensity of optical radiation, emitted by the plasma of COD, and the intensity profiles of sustaining laser beam (M2 = 6.6), transmitted through the plasma, were detected simultaneously. A considerable refraction of the sustaining laser beam up to 0.06 radians has been observed at low gas flow velocities when the front boundary of the plasma achieves the beam cross section with diameter close to the transverse diameter of the plasma. The state of the COD plasma was unstable in this case, following oscillations and extinction after the gas flow velocity had decreased. In main flow velocity range from 1.5 to 10 m/s and higher the plasma was stable and laser beam refraction was of the order of milliradians and could not affect plasma parameters.

Keywords:

continuous optical discharge (COD), laser plasmatron, absorption and diffraction of laser radiation in plasma