Scientists have taken a significant step forward in understanding the origins of explosive solar eruptions by identifying how a magnetic cage formed by the Sun’s global magnetic field can control the release of solar storms that threaten satellites, disrupt power grids, and endanger astronauts.
Predicting which magnetic structures on the Sun will erupt remains a central challenge in space weather forecasting.
A new study by researchers from Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous institute under the Department of Science & Technology (DST), Government of India, used advanced computational models to simulate the behavior of plasma interacting with magnetic fields through magnetohydrodynamic (MHD) simulations.
Their findings reveal that the Sun’s global magnetic field behaves like a magnetic cage, while the rapid build-up of magnetic twist provides the key to unlocking it. These eruptions are known as Coronal Mass Ejections (CMEs).
Magnetic Cage Mechanism Explains Solar Eruption Behavior
The research, led by Nitin Vashishtha, PhD student, and Dr. Vaibhav Pant, scientist at ARIES, simulated a CME using the “breakout model,” a leading theory explaining how solar eruptions are initiated.
The numerical simulations demonstrated that a stronger global magnetic field acts like a restraining cage, making it significantly harder for a CME to escape the Sun’s gravity. When researchers simulated a CME under a weaker background magnetic field, the eruption occurred successfully.
However, when the background magnetic field strength was slightly increased, the eruption was suppressed and ultimately failed.
This result supports a theory explaining a solar observation puzzle: Solar Cycle 24 was magnetically weaker than Solar Cycle 23 but produced a higher number of CMEs.
The simulations suggest that the weaker background magnetic field lowered the threshold required for eruptions, allowing smaller events to escape into space.
Also Read: Stealth Coronal Mass Ejection: A Silent Solar Event Travelled 150 Million km and Hit Earth Hard
Magnetic Cage Study Highlights Helicity Growth as Forecasting Tool
The second major result of the study provides a potential forecasting indicator. Researchers examined how injecting energy and magnetic twist — known as helicity — into the solar corona affects eruption outcomes.
They found that not just the amount of helicity, but the rate at which it builds, determines whether an eruption succeeds.
By tracking Absolute Net Current Helicity (ANCH), along with magnetic energy and Total Unsigned Current Helicity (TUCH), the team discovered that the growth rate of ANCH was the most reliable indicator of an impending eruption.
A slow increase in ANCH led to a “failed eruption,” where magnetic structures formed but fell back to the solar surface.
Magnetic Cage: Virtual Laboratory for Sun
In contrast, a rapid increase consistently preceded successful CMEs. In scenarios involving the fastest ANCH injection, simulations produced multiple successive CMEs from the same region.
“Our findings indicate that among these parameters, the time rate of absolute net current helicity can serve as the most effective indicator for distinguishing between various eruption scenarios,” the authors said.
Dr. Vaibhav Pant elaborated on the future direction:
“These simulations act as our virtual laboratory for the Sun, allowing us to test the fundamental physics of these massive eruptions. The next frontier is to translate these findings, particularly the importance of the energy build-up rate, into a reliable tool for forecasting real-world space weather events and protecting our vital infrastructure.”
The study is available here: https://doi.org/10.3847/1538-4357/adff54
