SPECIAL FEATURES AND TIME CHARACTERISTICS OF RADIATION FROM A PLASMA DURING A SHOCK DISCHARGE INTO AIR

The authors have made an experimental study of the temporal and spectral characteristics of radiation from a shock discharge of a plasma into air. It is shown that the radiation pulse is characterized by two stages differing strongly in duration. The first stage, whose duration does not depend on the plasma discharge conditions and exceeds the duration of the energy contribution in the discharge by a factor of 5-8, corresponds to the formation in air of complex plasma structures: mushroom, barrels, spherical plasma formation, and toroidal plasma vortices (TPV). In this stage the main part (congruent-to 85%) of the radiative energy is emitted. During the main energy contribution to the discharge (100-150-mu-sec) the plasma jet radiates along its axis in the spectral region lambda greater-than-or-similar-to 250-300 mm as a black body with a temperature of 10,000-20,000 K. The duration of the second radiative stage depends strongly on the plasma discharge regime and can have a duration up to 100 msec (TPV).