Indian researchers have identified a new way to understand the behavior of powerful solar eruptions that travel from the Sun to Earth, offering fresh insights that could improve space weather forecasting and help protect satellites, communication networks and power infrastructure. The findings are based on nearly three decades of observations and provide new evidence that the thermal properties of solar storms play a key role in determining their impact on Earth.

The study was conducted by researchers from the Indian Institute of Astrophysics (IIA), Bengaluru, an autonomous institute under the Department of Science and Technology (DST), Government of India. The research has been published in the Monthly Notices of the Royal Astronomical Society.

Three Decades Of Solar Data Reveal New Thermal Patterns

The research analyzed 29 years of observations, covering 1995 to 2024, across Solar Cycles 23, 24 and the rising phase of Solar Cycle 25. Scientists examined Interplanetary Coronal Mass Ejections (ICMEs), massive clouds of magnetized plasma released by the Sun that can trigger geomagnetic storms when they interact with Earth's magnetic field.

Using data from NASA's OMNI database, which combines measurements from multiple spacecraft near the Sun-Earth L1 point, the team studied how the temperature and pressure inside ICMEs changed during their journey toward Earth. The researchers calculated the polytropic index, a measure that describes how plasma evolves thermally.

The analysis found that nearly 45% of magnetic ejecta showed signs of heating rather than cooling during their travel through space. This challenges the long-held assumption that solar eruptions simply cool as they expand.

Stronger Solar Storms Linked To Heating Signatures

The study also found that the most intense geomagnetic storms were generally associated with ICMEs that remained in a heating state. These events typically featured stronger magnetic fields, faster expansion and higher magnetic pressure, making them more likely to disturb Earth's magnetosphere.

Researchers observed that heating signatures were more common during Solar Cycle 23, while cooling became more dominant during Solar Cycle 24, suggesting that the Sun's broader magnetic environment influences the thermal evolution of solar eruptions.

Findings May Strengthen Future Space Weather Forecasting

According to the researchers, combining thermal measurements with magnetic field observations could significantly improve forecasts of severe space weather. More accurate predictions could help governments, satellite operators, airlines and power utilities prepare for disruptions affecting GPS services, radio communications, aviation routes and electricity networks.

The team plans to incorporate observations from India's Aditya-L1 solar mission to monitor coronal mass ejections closer to the Sun and further refine forecasting models. Scientists say understanding the thermal evolution of solar storms could become an important new tool in predicting their potential impact on Earth.