Resonant scattering by excited ions as an indicator of the precipitation of charged particles into the atmosphere

Abstract

The results of two-frequency lidar sounding of the atmosphere from the altitudes of 100-500 km are presented. The data were obtained in 2017 at a lidar site located in Kamchatka. One lidar channel is applied to investigate the aerosol formations in the middle atmosphere and to issue the resonance scattering on excited ions of atomic nitrogen in the upper atmosphere. Nd:YAG laser operating on the wavelength of 532 nm is used in this channel. A dye laser with tunable frequency is applied in the second channel. The wavelength of 561.1 nm corresponds to the chosen dipole transition between the excited states of atomic oxygen. Defined light-scattering layers were discovered in the region of 200-400 km. They are caused by presence of excited states of atomic oxygen and nitrogen ions. The possibility of reconstruction of excited ions Nh-profile and determination of precipitated electron fluxes spectra by the lidar method is shown. The possibility of manifesting resonance scattering and formation of imaginary aerosol layers in the middle atmosphere is discussed.

Keywords

• atmosphere
• ionosphere
• lidar
• sounding
• scattering