Observations of Quasi-Periodic Electric Field Disturbances in the E Region before and during the Equatorial Plasma Bubble

Abstract

Wave-like electric field disturbances in the ionosphere before the Equatorial Plasma Bubble (EPB) are the subject of numerous recent studies that address the issue of possible short-term forecasting of EPB. We report the observations of the Equatorial Quasi-Periodic-Electric field Disturbances (QP-EDs) of the Field-aligned Irregularities (FAI) in the E region before the EPB occurrence in the F region. They are observed from 30 MHz coherent scatter radar during the SpreadFEx campaign 2005 carried out in Brasil. The presently reported QP-EDs at the equatorial E region below an altitude of 110 km are undescribed so far. Though QP-EDs characteristics vary on a day-to-day basis, consistent features are their intensification before the EPB, and their simultaneous occurrence with EPBs. This study highlights the monitoring of QP-EDs in the short-term forecasting of EPBs and further reveals the robust energetics of vertical coupling between E and F regions.

Statistical Characteristics of the Occurrence of ERI and FRI in the Equatorial Ionosphere With Observations of JULIA Radar

“…The stronger EEJ intensity during daytime will increase the occurrence rate of ESF after sunset (Tulasi Ram et al., 2007; Uemoto et al., 2010). In addition, quasi‐periodic electric field disturbances in E‐region before the occurrence of ESF can be used as a predictor of ESF occurrence (E. A. Kherani & de Paula, 2021). However, up to now, the connection between the ERI existing in EEJ and FRI at night in the equatorial region has not been revealed and needs to be further studied and supplemented.…”