Indian Astrophysicists Reveal Thermal Behaviour of Solar Storms to Boost Space‑Weather Forecasting

Indian scientists from the Indian Institute of Astrophysics (IIA) have analysed three decades of solar‑storm data to understand how the temperature of ICME s changes on their way to Earth. Their findings link the thermal state of these storms to their ability to cause geomagnetic storms , a matter of great relevance for India’s satellite, aviation and power‑grid sectors. Key Developments First long‑term statistical study of ICME thermal behaviour at 1 AU using data from 1995‑2024 (29 years) covering solar cycles 23, 24 and the rising phase of 25 . Application of a polytropic index framework to each magnetic ejecta , revealing heating in 45 % of events near solar maximum. Discovery of a shift from heating‑dominant ICMEs in Solar Cycle 23 to cooling‑dominant ICMEs in Solar Cycle 24 . Correlation of low polytropic index (heating state) with stronger magnetic fields, low plasma beta, compressed sheath regions and higher geoeffectiveness. Important Facts The study used the OMNI database , which merges observations from several L1 satellites to provide continuous solar‑wind parameters at Earth’s bow shock. By analysing pressure, temperature and density, the researchers derived the polytropic index for each event. The results challenge the earlier belief that ICMEs simply cool as they expand; instead, many are thermodynamically active, gaining heat during interplanetary travel. UPSC Relevance Understanding the thermal evolution of solar storms is vital for the Space Weather component of GS‑4 (Science & Technology). It directly impacts national security, disaster management, and the resilience of critical infrastructure such as communication satellites, GPS, aviation routes and power grids—topics frequently asked in the UPSC prelims and mains. The study also showcases the role of Indian research institutions and upcoming missions like Aditya‑L1 in advancing indigenous capabilities. Way Forward Future work will integrate early‑stage observations from Aditya‑L1 coronagraphs and solar‑wind instruments to track the thermal state of CMEs closer to the Sun. Combining the polytropic index with magnetic and plasma measurements could provide a multi‑dimensional diagnostic tool for more accurate space‑weather forecasts, helping policymakers mitigate the socio‑economic impacts of severe geomagnetic storms.