The interference structure of the laser light scattering cone behind the laser spark was observed for the first time. We propose consideration of the observed structure as a result of interference of the laser radiation, scattered by two or more self-focusing centers in laser spark air plasma. We have investigated the spatial distribution of the laser radiation scattered by the laser spark. These experiments differ from the previous ones by use of the four harmonics of Nd-laser radiation. As a source of radiation the Nd-laser installation was used with the master oscillator, operated on one transverse and longitudinal mode. The pulse duration was 10 ns, pulse energy - up to 20 J and beam divergence - 8 $DOT 10$+$MIN@5$/ rad. After the frequency conversion by means of the KDP crystals the second, third, and fourth harmonics radiation appeared with the energy up to 10 J (in fourth harmonic). In each of our experiments one laser harmonic radiation was focused into the hermetical chamber, filled with air (10 divided by 760 mm Hg). For the scattered radiation registration we photographed the scattering flat white screen, illuminated by this radiation. This screen was disposed parallel to the laser beam axis at the distance of 2 - 6 mm from it. We observed a cone-like symmetric respectively to the laser beam axis radiation scattering in the spark. That enables us to determine the maximum angle alpha of laser radiation deviation as a function of pressure p and wavelength lambda (or number of harmonic N). !3 (truncated)
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