The Role of Traveling Ionospheric Disturbances (TIDs) as a Possible Seeding Mechanism for Equatorial Plasma Bubbles

We are investigating the characteristics of TIDs and their possible role as seeding mechanisms for equatorial plasma bubbles (EPBs). We have a created database of identified EPB occurrences and the associated ionospheric characteristics (ion drifts, composition, etc.) using data from the Communication/Navigation Outage Forecasting System (C/NOFS) satellite and during its entire mission, starting in August 2008 and ending in November 2015, and the ongoing Ionospheric Connections Explorer (ICON) mission which starting in November 2019. We use a rolling ball method to automatically identify EPBs in the C/NOFS and ICON databases, employing multiple “ball” sizes to identify varying size bubbles. We present the initial statistics of our EPB database showing the distribution in local time and apex altitude. The results show a time delay between initial observations at low apex altitude at the terminator and at high apex altitudes consistent with a vertical propagation time of ~90 m/s. Concurrent EUV images from GOLD provide further information on EPB structure and evolution. The presence of TIDs is concurrent with the EPBs and their characteristics (wavelength, propagation speed, orientation, etc.) are determined by ground-based GPA total electron content (TEC) measurements and investigated for their role as a possible EPB seeding mechanism.