Multi-Probe Observations of Equatorial F Region Plassma Irregularities

Equatorial plasma irregularities have been the subject of extensive experimental and theoretical studies for several decades. We use plasma density measurements made during 30-31 January 2014 on board the low inclination C/NOFS satellite, the polar orbiting SWARM B and C and DMSPF18 satellites to examine in detail the longitudinal, latitudinal (altitudinal) and temporal variations of nighttime equatorial plasma irregularities over a large longitudinal sector centered over South America. These measurements often show deep plasma depletions with over two orders of magnitude extending up to about the equatorial ionization peaks. They are strongest over Brazil and in the pre-midnight sector and decrease significantly at later local times. These depletions exhibit large variations in their scale sizes and over longitudinal distances as short as about 100 km. We compare the satellite data with radar observations of small scale plasma irregularities at the Jicamarca Radio Observatory and with Digisonde observations over Brazil. We also briefly compare our data with results from previous observations and theoretical predictions from plasma irregularity models.