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Observations by Aditya-L1 help decode unusual dawn-time geomagnetic disturbances during strong solar storms

February 20, 2026 4 min read Science & Technology GS3 (Science & Technology Space)
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What Happened

  • Scientists using data from India's Aditya-L1 solar observatory have explained the cause of unusual magnetic disturbances observed on Earth's dawn side during strong geomagnetic storms.
  • The research focused on two intense geomagnetic storms that occurred on May 10 and October 10, 2024, during the peak phase of Solar Cycle 25, which produced auroras visible at unusually low latitudes.
  • The study found that during very strong storms, auroral current systems — normally confined to high-latitude (polar) regions — extend much farther towards the equator, but primarily on the dawn side, causing anomalous magnetic disturbances.
  • The research was led by the Indian Institute of Geomagnetism (IIG), Mumbai, in collaboration with ISRO scientists, combining Aditya-L1's in-situ particle and field measurements with a global network of ground-based magnetometers.

Static Topic Bridges

Aditya-L1 — India's First Solar Observatory

Aditya-L1 is India's first dedicated solar observatory, launched by ISRO on September 2, 2023, using the PSLV-C57 rocket. It was inserted into a halo orbit around the Sun-Earth Lagrange Point 1 (L1) on January 6, 2024, approximately 1.5 million km from Earth. From this vantage point, the satellite can continuously observe the Sun without any eclipses or occultation by the Earth.

  • Launch: September 2, 2023 (PSLV-C57); halo orbit insertion at L1: January 6, 2024
  • Location: Sun-Earth Lagrange Point 1 (L1), approximately 1.5 million km from Earth
  • Payloads: 7 scientific instruments — 4 for remote sensing of the Sun, 3 for in-situ observation
  • VELC (Visible Emission Line Coronagraph): Images the solar corona; uses AI for CME detection
  • SUIT (Solar Ultraviolet Imaging Telescope): Full-disk UV imaging (200-400 nm) using 11 filters
  • MAG (Magnetometer): Mounted on a 6-metre boom; measures interplanetary magnetic field
  • Other instruments: SoLEXS, HEL1OS (solar flares, X-rays), ASPEX, PAPA (solar wind particles)
  • Mission objectives: Study solar corona, solar wind, coronal mass ejections (CMEs), space weather, and magnetic field dynamics
  • India became the fifth space entity to place a satellite at L1 (after NASA, ESA, JAXA, and CNSA)

Connection to this news: The study leveraged Aditya-L1's in-situ instruments — particularly the magnetometer (MAG) and particle detectors (ASPEX, PAPA) — to correlate solar wind conditions measured at L1 with the anomalous dawn-side magnetic disturbances observed on Earth's surface, demonstrating the satellite's value for space weather research.

Geomagnetic Storms — Mechanism and Classification

A geomagnetic storm is a major disturbance of Earth's magnetosphere caused by efficient energy transfer from the solar wind. When a coronal mass ejection (CME) or high-speed solar wind stream carrying a southward-directed magnetic field reaches Earth, it interacts with the magnetosphere, compressing it on the dayside and stretching it on the nightside, driving intense electric currents.

  • Cause: Primarily coronal mass ejections (CMEs) — billions of tonnes of magnetised plasma ejected from the Sun at speeds of 250-3,000 km/s
  • Kp Index: Planetary 3-hour-range index measuring geomagnetic disturbance on a scale of 0-9; Kp 5 or above indicates a geomagnetic storm
  • NOAA G-Scale: G1 (Minor, Kp=5) to G5 (Extreme, Kp=9) — classifies storm severity based on impacts
  • Effects: Disruption of satellite operations, GPS errors, HF radio blackouts, power grid surges (e.g., 1989 Quebec blackout), visible auroras at lower latitudes
  • Ring current: A toroidal current system at 3-8 Earth radii; intensifies during storms, measured by the Dst (Disturbance storm-time) index
  • Key distinction: Geomagnetic storms (magnetosphere disturbance) vs solar flares (electromagnetic radiation) vs solar energetic particle events (high-energy particles)

Connection to this news: The May and October 2024 storms were classified as severe geomagnetic events (G4-G5 level) that produced auroras visible at unusually low latitudes, providing a unique opportunity for Aditya-L1 to study how storm-time currents redistribute during extreme space weather events.

Solar Cycle 25 — Current Phase and Significance

The Sun follows an approximately 11-year cycle of magnetic activity, marked by changes in the number of sunspots, solar flares, and CMEs. Solar Cycle 25 began in December 2019 and reached its peak (solar maximum) around mid-2024, with elevated activity expected to continue through 2026.

  • Solar Cycle 25: Began December 2019; predicted peak: 2024-2025 (actual peak observed around mid-2024)
  • Sunspot number at peak: Significantly exceeded initial predictions of a "moderate" cycle; actual activity has been comparable to or stronger than Solar Cycle 24
  • Solar maximum significance: Higher frequency and intensity of solar flares, CMEs, and geomagnetic storms during this phase
  • Monitoring bodies: NOAA Space Weather Prediction Center (SWPC), ISRO's Aditya-L1, ESA's Solar Orbiter
  • January 2026 event: The Sun released the largest solar radiation storm in over 20 years, further highlighting the elevated activity of this cycle
  • Carrington Event (1859): The most powerful geomagnetic storm on record (estimated Dst: -1760 nT); a similar event today could cause trillions of dollars in damage to global infrastructure

Connection to this news: The study's focus on extreme geomagnetic storms during the peak of Solar Cycle 25 is scientifically timely, as the elevated solar activity provides rare data points for understanding how Earth's magnetosphere responds to the most intense space weather events — knowledge critical for protecting satellite infrastructure and power grids.

Key Facts & Data

  • Aditya-L1 launch: September 2, 2023 (PSLV-C57); L1 orbit insertion: January 6, 2024
  • Location: L1 point, approximately 1.5 million km from Earth
  • Payloads: 7 instruments (4 remote sensing, 3 in-situ)
  • Storms studied: May 10, 2024, and October 10, 2024 (Solar Cycle 25 peak)
  • Research led by: Indian Institute of Geomagnetism (IIG), Mumbai, with ISRO
  • NOAA G-Scale: G1 (Minor) to G5 (Extreme)
  • Solar Cycle 25: Began December 2019; peak around mid-2024; elevated activity expected through 2026
  • Sun-Earth distance at L1: approximately 1.5 million km (about 1% of the total Sun-Earth distance)