Publication Date:
2019
Description:
Abstract
This study examines the response of the nighttime Thermosphere‐Ionosphere System (TIS) over a dip equatorial station, Trivandrum (8.5o N, 77o E, 0.5o dip lat.) to Prompt Penetration Electric Field (PPEF) events occurred on 05 January 2016 and 06 March 2016. The investigation is based on nightglow emission measurements at wavelengths OI 777.4 nm, OI 630.0 nm and OI 557.7 nm using a multi‐wavelength nighttime photometer. These emissions emanate from different altitude regions of the TIS, i.e. 557.7 nm from ~100 km, 630.0 nm from ~220 km and 777.4 nm from ~350 km respectively. It has been observed that, during the westward PPEF event, the intensities of 777.4 nm and 630.0 nm nightglow emissions enhance whereas during the eastward PPEF event the intensities decrease. Similarly, though it is not very prominent, 557.7 nm emission also exhibits a small enhancement/decrease during the westward/eastward PPEF events. The ionospheric base height obtained from a collocated Digital Ionosonde shows that during the eastward (westward) PPEF event the ionospheric layer moves upward (downward). The downward (upward) layer movement increases (decreases) the plasma density in the centroid of these airglow emissions, which in turn enhances (decreases) the emission rates. The study demonstrates the coupling between interplanetary medium and neutral TIS during nighttime PPEF events.
Print ISSN:
2169-9380
Electronic ISSN:
2169-9402
Topics:
Geosciences
,
Physics
