CHENNAI: Providing new insights on solar eruptions, India's first dedicated solar observation spacecraft, Aditya-L1, has revealed that they do not always expand uniformly. The findings could help scientists improve space weather predictions and assess the potential impact of solar activity on satellites.

These powerful eruptions from the Sun affects several technologies people depend on every day, including GPS navigation, satellite communication, electricity networks, and mobile services.

Using observations from Aditya-L1, ISRO scientists recently discovered that solar eruptions do not always expand uniformly. According to the findings, observations from the Visible Emission Line Coronagraph (VELC) aboard the vessel have revealed that a Coronal Mass Ejection (CME, ) a massive release of charged particles and magnetic fields from the Sun, expanded asymmetrically in the region close to the solar surface.

Their analysis combining imaging observations, spectroscopic measurements from VELC, and three-dimensional modelling found that conventional models, which assumed CMEs expanded symmetrically like bubbles, could not reproduce the spectral patterns recorded by the instrument.

However, when scientists introduced asymmetric lateral expansion and a tilted structure into their three-dimensional model, the simulated spectra closely matched the actual VELC observations. This provided evidence that the CME had expanded unevenly in the inner corona, challenging the earlier assumption that such eruptions always maintain a uniform structure.

The discovery is significant, because the shape of a CME can influence how it travels through space. Depending on its structure, a solar eruption may experience different levels of resistance from the solar wind, affecting its speed and the time it takes to reach Earth.

When powerful CMEs interact with Earth's magnetic field, they can trigger geomagnetic storms that have the potential to disrupt satellite operations, GPS navigation, radio communications and, in severe cases, electricity transmission networks.

The study demonstrates how Aditya-L1's VELC instrument can help scientists determine the three-dimensional structure of solar eruptions from a single observation point. These findings could help scientists better assess potential threats to Earth's technology-dependent infrastructure and support the design and development of satellites with improved protection against the effects of solar storms.

Launched on September 2, 2023, aboard the PSLV-C57 from the Satish Dhawan Space Centre in Sriharikota, Aditya-L1 is India's first space-based solar observatory. The spacecraft was placed in a halo orbit around the Sun-Earth Lagrange Point 1 (L1), approximately 1.5 million km from Earth. Its primary objective is to study the Sun's outer layers.