In early May 2024, Earth encountered one of the most severe solar storms in over two decades, induced by the highly active sunspot AR13664. This sunspot released several X-class flares and coronal mass ejections (CMEs) aimed at Earth, leading to a geomagnetic storm with a Dst index reaching -412 nT. The storm’s magnitude matched the most intense disturbances since 2003 and caused widespread disruptions in communication and GPS systems. It featured not only powerful X-class flares but also numerous M-class and C-class flares, many of which were associated with halo CMEs—CMEs aimed directly at Earth.
Observations from Ground
Solar flares, the bursts of energy due to magnetic reconnection on the sun, are categorized from B to X, with each class representing a tenfold increase in energy. X-class flares, like the recorded X 5.8, are the most intense and capable of causing significant technological disruptions. The next tier, M-class flares, are slightly less powerful but can still influence Earth’s geomagnetic environment.
This latest geomagnetic storm is comparable in intensity to the historic 1859 Carrington Event. The high latitudes experienced severe impacts, including disruptions to trans-polar flights, while the Indian sector saw relatively minor effects due to the timing of the storm’s peak. Ground observations from India indicated significant ionospheric disturbances, particularly in changes to the Total Electron Content (TEC), a key measure of ionospheric density.
Observations from Space
From a space-based perspective, the Indian Space Research Organisation (ISRO) actively monitored the event using its Aditya-L1 and Chandrayaan-2 satellites. Aditya-L1’s instruments, including the Solar Wind Ion Spectrometer (SWIS) and the SupraThermal and Energetic Particle Spectrometer (STEPS), detected increased solar wind speed, elevated temperatures, and heightened fluxes of energetic particles like protons and alpha particles. These instruments are crucial for understanding the solar wind’s properties and its effects on space weather.
Observations by Aditya-L1
Chandrayaan-2, orbiting the moon, also contributed valuable data, particularly through the X-ray Spectrometer Monitor (XSM), which recorded significant solar flare activity and the corresponding effects on the local high-energy particle environment.
The storm’s impact extended to spacecraft operations, with ISRO’s Master Control Facility reporting disturbances that affected the functioning of various satellite components. Despite these challenges, the overall integrity of the spacecraft remained intact, and no significant degradations in service were reported by ISRO’s Navigation Centre.
This event underscores the need for continued vigilance and preparedness in the face of solar activity, highlighting the interconnectedness of space weather and technological systems on Earth.