Causal links to persisting daytime equatorial plasma bubbles over Asia-Pacific region following the geomagnetic storm on 01 December 2023.

A strong geomagnetic storm that occurred on 01-December-2023 triggered unusual equatorial plasma bubbles (EPB) over 100-140°E longitudes, which persisted for several hours after sunrise on the next day. FORMOSAT-7/COSMIC-2 and ground-based global navigation satellite system observations, and Global Ionospheric Specification (GIS) electron density are used to investigate this long-lasting unseasonal EPB episode in the solstice period over Asia-Pacific. The results show that in presence of elevated F-layer bottom-side aided by prompt penetration electric field (PPEF), large-scale traveling ionospheric disturbances (LSTID) generated by high-latitude Joule heating seeded the instability soon after sunset. However, it is a second phase of reinforced EPBs generated in the post-midnight period triggered by another group of larger LSTIDs that uncharacteristically prolonged into daytime hours. The GIS observations further provide evidence that the extremely low background ionization on the following day due to composition changes during the negative storm phase enabled these EPBs to survive even after sunrise before the depleted flux tubes were refilled by fresh ionization. The coordinated ground- and space-based observations demonstrate the causal links for the rare unseasonal EPBs occurring in the post-sunset and post-midnight periods over the same longitude sector and the latter persisting several hours after sunrise with potentially enduring space weather implications on satellite communication and navigation.