In the realm of space weather and solar physics, a team of researchers led by Christian Möstl from the University of Graz, Austria, has made significant strides in understanding the evolution of interplanetary coronal mass ejections (ICMEs). ICMEs are large expulsions of plasma and magnetic field from the Sun’s corona that can have profound impacts on space weather and, consequently, on our technological infrastructure in space and on Earth. The team’s work, published in the journal Astronomy & Astrophysics, provides crucial insights into how these solar events evolve as they travel through interplanetary space.
The researchers have compiled one of the most comprehensive catalogs of ICMEs to date, encompassing 1976 events observed by 11 space missions over a span of 34 years, from December 1990 to August 2025. This catalog includes data from missions such as Parker Solar Probe, Solar Orbiter, and BepiColombo, which have provided valuable observations near the Sun, bridging a significant observational gap. The team identified and added boundaries of an additional 807 events, constituting 40.8% of the catalog, to enhance the dataset.
Using this extensive catalog, the researchers conducted the most extensive analysis to date of the total ICME magnetic field values as a function of heliocentric distance, which is the distance from the Sun. They found that a single power law can describe the evolution of the mean total magnetic field and maximum field within the magnetic obstacle (MO) of an ICME, from as close as 0.07 astronomical units (au) to as far as 5.4 au. The power law exponents for the mean total magnetic field and maximum field are -1.57 and -1.53, respectively.
However, the researchers noted a strong inconsistency when they extended the power law to the solar photosphere. The magnetic field magnitudes predicted by the power law differed by 2 to 4 orders of magnitude from those observed in quiet Sun regions and active regions, respectively. To address this discrepancy, they introduced a multipole-type power law with two exponents, k1 = -1.57 and k2 = -6, which relates the ICME magnetic field magnitude to an average solar active region field strength.
The practical applications of this research for the energy sector, particularly the space-based segment, are significant. Understanding the evolution of ICMEs and their magnetic fields is crucial for improving space weather forecasting. Accurate forecasts can help protect satellites, power grids, and other critical infrastructure from the potentially devastating effects of solar storms. By providing observational constraints for the evolution of ICMEs from the Sun to the heliosphere, this research contributes to the development of more reliable space weather prediction models, ultimately enhancing the resilience of our energy systems to space weather events.
In summary, the work of Möstl and his team represents a significant advancement in our understanding of ICME evolution. Their findings offer valuable insights for the energy sector, particularly in the realm of space weather forecasting and mitigation. As we become increasingly reliant on space-based technologies, the ability to predict and prepare for solar storms becomes ever more critical, making this research all the more relevant and impactful.
This article is based on research available at arXiv.