Probing the possible trigger mechanisms of an equatorial plasma bubble event based on multistation optical data

Abstract

We analyze an equatorial plasma bubble (EPB) event observed in optical 630 nm image data simultaneously from Gadanki (13.5°N, 79.2°E), Kolhapur (16.8°N, 74.2°E), India. The total electron content data from Gadanki together with the ionosonde data from an equatorial Indian station, Tirunelveli (8.7°N, 77.8°E) confirmed the association of observed EPB event with equatorial spread F (ESF). The optical 630 nm images from a farther low-latitude Indian station Ranchi (23.3°N, 85.3°E) show clear signatures of tilted east-west wave structures propagating toward equator. Further, the upward wave energy noted in mesospheric airglow data was found to be negligible. These data suggest that possibly the off-equatorial tilted east-west structures triggered the observed EPB/ESF event.