Development of the Storm‐Induced Ionospheric Irregularities at Equatorial and Middle Latitudes During the 25–26 August 2018 Geomagnetic Storm

Abstract

The 25-26 August 2018 space weather event was classified as the third largest geomagnetic storm of the twenty fourth solar cycle (in terms of the Dst minimum excursion) after the March 2015 and June 2015 geomagnetic storms. The slowly moving coronal mass ejection (CME) occurring on 20 August 2018 was expected to cause a minor geomagnetic activity only, but surprisingly it turned into a strong geomagnetic storm at the very end of the twenty fourth solar cycle. The space weather events of such intensity occurring during the solar minimum period and at the background of the very low ionospheric density can result in a strong ionosphere-thermosphere response. Several recent papers were devoted to the investigation of the positive and negative ionospheric storm effects on the ionospheric density distribution over the globe (Astafyeva et al., 2020;Mansilla & Zossi, 2020;

Irregularities in the African ionosphere associated with total electron content anomalies observed during high solar activity levels

“…The results of our study support that the TEC configuration correlates with irregularities mostly in the low-latitude ionosphere and has a nighttime effect. This is also observed in the results of Cherniak and Zakharenkova, 2022, who observed that nighttime until sunrise irregularities persist at low latitudes.…”

GOLD Mission's Observation About the Geomagnetic Storm Effects on the Nighttime Equatorial Ionization Anomaly (EIA) and Equatorial Plasma Bubbles (EPB) During a Solar Minimum Equinox

“…The irregularities manifest as equatorial plasma bubbles (EPBs) in airglow ionospheric images. Electric field perturbations during geomagnetic active periods are reported to enhance (Basu et al, 2010;Cherniak & Zakharenkova, 2022;Kil et al, 2016;Patra et al, 2016;Tulasi Ram et al, 2008;Zakharenkova & Cherniak, 2020) and sometimes inhibit (Aarons, 1991;Abdu et al, 1995;Spogli et al, 2016) the irregularities. Using the AE-parameterized Fejer-Scherliess model for disturbance vertical drifts versus storm time and local time, Martinis et al (2005) were able to summarize these apparently contradictory effects.…”

Characterization of local time dependence of equatorial spread F responses to substorms in the American sector

“…The equatorial ionospheric perturbations during disturbed conditions are affected by the combined effects of PPEF and DDEF from the high latitude ionosphere. Hence the effect of geomagnetic storms in the context of generation/inhibition of ESF is an important space weather concern and has received a lot of attention in the recent past (Li et al 2018;Cherniak 2022;Zhang et al 2022). Li et al (2018) showed that strong southward IMF Bz excursions during storm rapidly raised the F layer near sunset and led to the development of intense equatorial plasma irregularities.…”