The coronal mass ejection productivity of solar active region 13664/8
Abstract
In May 2024, NOAA active region (AR) complex 13664/8 was one of the most productive regions of the current solar cycle, producing 12 X-class flares and over 20 coronal mass ejections (CMEs) and triggering the strongest geomagnetic storm since 2003. We investigate why this AR complex was so CME-productive. Using primarily SDO/AIA and SDO/HMI observations, we analyzed its photospheric magnetic evolution, eruption sources, eruption waiting times, and magnetic parameters in comparison with five other ARs. The region initially contained only AR 13664 and exhibited limited flare activity until AR 13668 emerged on May 4, after which clustered major flares and CMEs occurred. Rapid, complex flux emergence substantially increased the region's area, magnetic flux, complexity, and nonpotentiality. The increased complexity was manifested by at least 12 emerging bipoles and six collisional polarity inversion lines (cPILs) formed between nonconjugated polarities, all showing sustained collision and shearing and serving as eruption sources. Decay index distributions show systematically lower critical heights (<45 Mm) above CME source regions. The CME waiting time distribution exhibits two peaks, suggesting that multiple cPILs enhanced CME productivity by increasing both recurrent CMEs from the same source and disturbance-triggered CMEs from nearby sources. These results indicate that, in addition to sufficient nonpotentiality and rapid background-field decay, high magnetic complexity accompanied by dynamical collisional shearing at multiple cPILs was crucial for the extreme CME productivity of AR 13664/8.
Versions
Related
- SOLACE: A Contrastive Learning Framework for Predicting Solar Proton Events and Geomagnetic Storms from Flare–Coronal Mass Ejection Events
- Breakout/Interchange Reconnection as a driver of Jets, Fast Coronal Mass Ejection, and Solar Energetic Particles
- Cross-layer coupling in active-region upflows: Statistical connections between photospheric magnetic field, chromospheric activity, and coronal blueshifts
- Breakout/Interchange Reconnection as a Driver of Jets, Fast Coronal Mass Ejection, and Solar Energetic Particles
- Revisiting the Role of Global Magnetic Variables in Coronal Heating of Solar Active Regions
BibTeX
@misc{liu2026coronal,
title = {{The coronal mass ejection productivity of solar active region 13664/8}},
author = {Lijuan Liu and Yuming Wang and Quanhao Zhang and Jingnan Guo and Yutian Chi},
howpublished = {arXiv},
year = {2026},
month = jul,
doi = {10.48550/arxiv.2607.14636},
eprint = {2607.14636},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.14636},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The coronal mass ejection productivity of solar active region 13664/8
AU - Lijuan Liu
AU - Yuming Wang
AU - Quanhao Zhang
AU - Jingnan Guo
AU - Yutian Chi
PY - 2026
DA - 2026/07/17
PB - arXiv
DO - 10.48550/arxiv.2607.14636
UR - https://arxiv.org/abs/2607.14636
AB - In May 2024, NOAA active region (AR) complex 13664/8 was one of the most productive regions of the current solar cycle, producing 12 X-class flares and over 20 coronal mass ejections (CMEs) and triggering the strongest geomagnetic storm since 2003. We investigate why this AR complex was so CME-productive. Using primarily SDO/AIA and SDO/HMI observations, we analyzed its photospheric magnetic evolution, eruption sources, eruption waiting times, and magnetic parameters in comparison with five other ARs. The region initially contained only AR 13664 and exhibited limited flare activity until AR 13668 emerged on May 4, after which clustered major flares and CMEs occurred. Rapid, complex flux emergence substantially increased the region's area, magnetic flux, complexity, and nonpotentiality. The increased complexity was manifested by at least 12 emerging bipoles and six collisional polarity inversion lines (cPILs) formed between nonconjugated polarities, all showing sustained collision and shearing and serving as eruption sources. Decay index distributions show systematically lower critical heights (<45 Mm) above CME source regions. The CME waiting time distribution exhibits two peaks, suggesting that multiple cPILs enhanced CME productivity by increasing both recurrent CMEs from the same source and disturbance-triggered CMEs from nearby sources. These results indicate that, in addition to sufficient nonpotentiality and rapid background-field decay, high magnetic complexity accompanied by dynamical collisional shearing at multiple cPILs was crucial for the extreme CME productivity of AR 13664/8.
ER -