Insights from Historical Space Weather Events: 1972 and 1989 Reviewed

Recent research by Bruce T. Tsurutani and colleagues, titled "Review of the August 1972 and March 1989 Space Weather Events: Can We Learn Anything New From Them?" (arXiv:2409.00452), provides updated summaries of significant space weather events from August 1972 and March 1989. This paper compares these events to the historic Carrington event of 1859 and other major occurrences, highlighting the diverse energy outputs from solar active regions.

The study concludes that solar active regions release energy in various forms, including X-rays, extreme ultraviolet (EUV) photons, visible light, and coronal mass ejections (CMEs). These energy forms can lead to other energetic phenomena such as solar energetic particles (SEPs) and magnetic storms. Notably, the research indicates that there is no consistent one-to-one relationship between these energy outputs, suggesting that the energy distribution varies significantly from one space weather event to another.

Particularly, the authors found that if the magnetic cloud conditions during the August 1972 event had been different, a more intense magnetic storm could have occurred, potentially exceeding the Carrington event in severity. The paper also discusses the mechanisms behind SEPs accelerated at interplanetary CME shocks, noting that the gradient drift mechanism at quasi-perpendicular shocks could lead to harder spectra and higher fluxes.

This research is significant as it enhances our understanding of space weather dynamics and the potential impacts on Earth, particularly regarding the safety of satellites and other technologies sensitive to solar activity. The findings underscore the importance of monitoring solar events to better predict their effects on our planet and technological systems.