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.
