Causes of the glow of the anomalous secondary flow in supersonic clustered jets excited by a high-voltage electron beam

The role of clustered particles in the formation of a secondary flow (“wake”) occuring at the gas expiring into a rarefied medium in condensation modes is established. The “wake” boundaries were found by comparing the spectral and photometric measurements. Possible mechanisms for initiating luminescence in “wake” are considered. The role of energy exchange of clusters with background gas in the afterglow of the “wake” has been found out. The wavelengths and corresponding transitions in the neutral (Ar-I) and once ionized (Ar-II) argon atoms, which determine the anomalous glow, were discovered. The lifetimes in the excited state of particles in the central part and on the periphery of the clustered flow are detected. The effect of condensation on the background gas penetration into the primary traditional supersonic jet and into the “wake” zone is found.