Multi-wavelength optical imaging of ionospheric plasma depletions

Abstract

An all sky optical imaging system using a high gain image intensifier has been built to study a class of equatorial spread-F irregularities which are known as plasma depletions. The 630 nm and 777.4 nm nightglow emission lines, which come essentially from regions about 50 km below the F2-peak and F2-peak respectively, are used to study the plasma depletions when they are located at these altitudes. The newly developed optical imaging system and a VHF Scintillation receiver were operated along with the digital ionosonde from SHAR, India (14°N, 80°N, dip 14°N), during February 1993. Preliminary results are presented here to demonstrate the system capabilities for studying ionospheric plasma depletions.