Unveiling Key Factors in the Solar Eruptions Leading to the Solar Superstorm in 2024 May

TL;DR

This study investigates the magnetic configurations and flux emergence rates in NOAA AR 13664/8 that led to a major solar superstorm in 2024, revealing key factors influencing CME eruptions and geomagnetic impacts.

Contribution

It uncovers how rapid magnetic flux emergence and specific photospheric magnetic structures along PILs drive homologous CMEs and extreme geomagnetic storms, advancing understanding of eruption mechanisms.

Findings

Identified source regions of seven halo CMEs along two PILs.

Correlated flux emergence rates with CME intensities.

Linked magnetic field gradients to eruption occurrences.

Abstract

NOAA Active Region (AR) 13664/8 produced the most intense geomagnetic effects since the ``Halloween'' event of 2003. The resulting extreme solar storm is believed to be the consequence of multiple interacting coronal mass ejections (CMEs). Notably, this AR exhibites an exceptionally rapid magnetic flux emergence. The eruptions we are focusing on all occurred along collisional polarity inversion lines (PILs) through ``collisional shearing'' during a three-day period of extraordinarily high flux emergence ($\sim$10$^{21}$ Mx hr$^{-1}$). Our key findings reveal how photospheric magnetic configurations in eruption sources influence solar superstorm formation and geomagnetic responses, and link exceptionally strong flux emergence to sequential homologous eruptions: (1) We identified the source regions of seven halo CMEs, distributed primarily along two distinct PILs, suggesting the presence of two groups of homologous CMEs. (2) The variations in magnetic flux emergence rates at the source regions correlate with CME intensities, potentially explaining the two contrasting cases of complex ejecta observed at Earth. (3) Calculations of magnetic field gradients around CME source regions show strong correlations with eruptions, providing crucial insights into solar eruption mechanisms and enhancing future prediction capabilities.