Gravity wave seeding of equatorial plasma bubbles: An investigation with simultaneous F region, E region, and middle atmospheric measurements

In this paper, we examine the lidar observations of middle atmospheric temperature and E and radar observations of F region FAI from Gadanki to investigate the gravity wave seeding hypothesis of equatorial plasma bubble (EPB). Temperature observations provide clear evidence of upward propagation of gravity waves, having wave period of 20 min-2 h. Simultaneous observations of E region FAI drifts, which were attributed to E x B drift, showed similar variations. Vertical wavelength estimated from the height profile of temperature data and cross correlation analysis of temperature and E region FAI drift variations showed remarkably high correlation, indicating the propagation of gravity waves from the middle atmosphere to the E region. On the nights of such observations, periodic plume activities were observed and, interestingly, remarkable correlation is found among the gravity wave periods in the middle atmosphere, E region FAI drifts, and temporal separation of plume occurrence which supports the gravity wave seeding of ESF bubble.