| Abstract : | Studies on ionospheric scintillations have always been important to understand the behavior of the ionosphere particularly at low as well as equatorial latitudes. A low latitude study of ionospheric scintillation, especially around the Equatorial Ionization Anomaly (EIA). It is essential to understand the dynamics of ionospheric variation and related physical processes like TID’s and plasma bubble formation. The results that have been obtained during our analysis emphasize the need for such characteristic studies. The study involves NavIC (The Indian Regional Navigation Satellite System, with an operational name of NavIC-Navigation with Indian Constellation) amplitude scintillation (S4c) observations over Indore, located near the northern crest of the EIA, under disturbed ionospheric conditions on September 8, 2017, which essentially falls in the declining phase of 24th solar cycle. The observations clearly show that the scintillation of the NavIC signal follows the Nakagami-m distribution along with the α-µ distribution. This is a clear depiction of the fading effect caused by scintillation on NavIC signals for September 8, 2017, where the values of carrier to noise ratio (dB-Hz) for PRNs 2, 5 and 6 have dropped below 30 dB-Hz and have approached to value of zero between 22:00 to 0 LT(h). The severity of S4c index during that time peaked beyond the value of 0.5 as observed from PRN 2 of NavIC and the value of intensity fading that has reached up to -8dB. This paper, for the first time, conducts an intensity fading study over region near EIA using NavIC for an intense geomagnetic storm observed on September 8, 2017, where the Dst Index has dropped to a minimum value of 124nT. |
