Indian Scientists Develop Novel Method to Measure CME Expansion for Improved Space Weather Prediction
Delhi, January 30, 2025 – Researchers at the Indian Institute of Astrophysics (IIA), an autonomous institute under the Department of Science and Technology (DST), have devised an innovative method to determine the instantaneous expansion speed and radial size of Coronal Mass Ejections (CMEs) as they traverse space. This breakthrough could significantly enhance predictions of CMEs’ impact on Earth’s communication systems and power grids.
CMEs are massive clouds of magnetized plasma ejected from the Sun, which can trigger geomagnetic storms upon reaching Earth. These storms have the potential to disrupt satellite communications, cause power outages, and impact global navigation systems. The duration and intensity of such disturbances are influenced by the radial dimension of CMEs, a factor that has remained inadequately understood due to limited observational methods.
Traditionally, the expansion speed of CMEs has been estimated using single-point in situ measurements, which provide incomplete data. To address this challenge, IIA researchers developed a technique that calculates the instantaneous expansion speed using observations from a single-point spacecraft. By analyzing the accelerations of CME substructures—including the leading edge, center, and trailing edge—they were able to estimate propagation speeds at any given moment.
“Our non-conventional approach utilizes the propagation speed of any two CME substructures at the same instance to determine the instantaneous expansion speed,” said Dr. Wageesh Mishra, a faculty member at IIA and co-author of the study.
The study also examines the aspect ratio of CMEs—how their radial dimension changes relative to their increasing distance from the Sun. The researchers found that this ratio initially increases, then stabilizes, before eventually decreasing in interplanetary space. This new insight challenges previous assumptions about CME expansion.
The effectiveness of this method was demonstrated through a case study of a CME that erupted on April 3, 2010. Data from NASA and ESA’s SOHO (Solar and Heliospheric Observatory), STEREO (Solar Terrestrial Relations Observatory), and Wind spacecraft provided critical validation.
“The accurate estimation of a CME’s expansion speed is crucial for predicting its arrival time and understanding how its substructures evolve in space,” said Anjali Agarwal, a Ph.D. student at IIA and lead author of the study.
Looking ahead, researchers plan to utilize single-point in situ observations from India’s first space-based solar observatory, Aditya-L1. The Aditya Solar Wind Particle Experiment (ASPEX) onboard this spacecraft will provide valuable data to further refine their non-conventional approach.
This research represents a significant step toward improving space weather forecasting, potentially mitigating the adverse effects of solar activity on Earth’s technological infrastructure.
Source: PIB
