Equatorial Plasma Bubbles Encounter With the Nighttime Ionosphere Enhancement

Abstract On the two consecutive days of February 26–27, 2014, the all‐sky airglow imager in Qujing observed Equatorial Plasma Bubbles (EPBs) dissipating more rapidly than those that appeared before and after. While these rapidly dissipating EPBs were present, the Hainan COherent‐scatter Phased Array Radar (HCOPAR) detected Field‐Aligned Irregularities (FAIs) within them. These FAIs first descended and then rose. The vertical extent of the fluctuations exceeded 100 km. Observations from four ionosondes at different latitudes showed a consistent pattern over the two nights. The F‐layer height initially ascended and then rapidly descended. Plasma from higher altitudes was compressed to lower altitudes, which resulted in a significant increase in peak density. As a result, Nighttime Ionosphere Enhancement (NIE) occurred. At first, the FAIs descended along with the F‐layer. After a while, they began to rise again. The downward movement is believed to have accelerated the decay of EPBs in the NIE region.