GSLV effect on Earth’s lower ionosphere

The effect of the rocket exhaust products on the D-region of the ionosphere is investigated with the help of Very Low Frequency (VLF) electromagnetic wave along the Earth-ionosphere waveguide. VLF is a very useful tool to study the Earth's lower ionospheric disturbances. The changes in the electron density profile are computed from the observed VLF signal perturbations after the rocket launch. We report the effect of the rocket exhaust on the lower ionosphere at an altitude around 58 km. The effect is primarily caused by localized free-electron depletion by water molecules by the process of attachment, decreasing the electrical conductivity of the ionosphere. The electron depletion is supposed to be formed by the rocket exhaust products of the 1st stage burn of Geosynchronous Launch Vehicle (GSLV) rocket launched from Sriharikota, India, on 27th August 2015 at 11:22 UT (16:52 IST). A Long Wave Propagation Capability (LWPC) model study also supports our findings.