Periodicity in the occurrence of equatorial plasma bubbles
Monday, 15 December 2014
We investigate the seeding mechanism of equatorial plasma bubbles by examining their occurrence characteristics in satellite observations. For this purpose, we analyze the measurements of the plasma density in 2008–2012 by the Planar Langmuir Probe instrument onboard the Communication/Navigation Outage Forecasting System satellite. The satellite data were segmented in the region where series of bubbles occur, and periodgrams for the data segments in the longitude range of about 30 degrees were obtained. Our preliminary results obtained from the observations in 2008 show that the dominant period in the occurrence of bubbles is about 5 degree (500~600km) in longitude. Periodic bubbles predominantly occur in the Atlantic-African sectors. By extending the analysis to the observations in 2009–2012, we investigate the variation of the periodicity with longitude, season, and solar cycle. The periodicity in the occurrence of bubbles and its association with gravity waves are discussed.