Study of ionospheric TEC during space weather event of 24 August 2005 at two different longitudes

Response of low latitude ionosphere to the geomagnetic storm of 24 August 2005 has been studied using total electron content (TEC) data obtained from the global positioning system (GPS) receivers located at Udaipur (Geog. Lat. 24.67°N, Geog. Long. 73.7°E) and Yibal (Geog. Lat. 22.18°N, Geog. Long. 56.11°E), near the northern crest (∼16°N Mag. Lat.) of the equatorial ionization anomaly. This study has also been substantiated with the ground based ionosonde observation at New Delhi, a low latitude station. The TEC on 24 August reveals two well defined humps. The enhancements in TEC have been attributed to the prompt penetration electric fields, inferred from the height variations of the F-layer peak using the ionosonde observations. In addition to these fields, contribution of the abnormal equatorial plasma fountain during the late afternoon hours has been proposed to explain the second hump in TEC.

► Episodes of PP electric field during geomagnetic storm of 24 August 2005 inferred.
► Two humps in TEC near the northern crest of EIA have been observed.
► Effect of disturbance dynamo fields inferred.