space weather;
geomagnetic storm;
equatorial ionosphere;
total electron content;
electron density;
TOTAL ELECTRON-CONTENT;
F3;
LAYER;
ADDITIONAL LAYER;
MAGNETIC STORMS;
DISTURBANCE;
FIELDS;
MODEL;
INTERPLANETARY;
THERMOSPHERE;
FREQUENCY;
D O I:
10.1029/2024JA033368
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
This study investigates the effects of the great geomagnetic storm of May 10-11, 2024, on the plasma density distribution in the ionosphere over the Indian equatorial and low-latitude regions. We utilized Vertical Total Electron Content (VTEC) as a proxy to understand the plasma density distribution. In conjunction with the equatorward neutral wind from the auroral region, the strom generated strong convective electric fields, penetrating down to the dip-equator, played a cruicial role in causing VTEC reduction at night (main phase) and enhancement during the day (recovery phase) on 11 May. Simultaneously, a decrease in VTEC of over 60% was observed in Bhopal, an equatorial ionization anomaly crest region. Undulations in the VTEC at the dip-equator correlated well with interplanetary electric field (IEFy) and magnetic field (Delta ${\Delta }$H) fluctuations. Analysis of the AE index suggests a strong equatorward wind surge due to intense auroral heating during the storm. Since the great storm occurred at night over India, meridional wind circulation played a prominent role. This study highlights the need for a more detailed analysis using multiple instruments and models to understand the response of the Indian equatorial and low-latitude regions during geomagnetic storms.