Why in News? ISRO said it closely monitored (through Aditya-L1 and Chandrayaan-2 orbiter) and captured the signatures of the powerful solar storm triggered by the highly active sunspot region (AR13664), that impacted Earth

The astronomers of the IIA (Bengaluru), who captured the auroras (triggered by the solar storm) around the IAO in Hanle (Ladakh), explained why auroras were seen across a wider region, including India.

What’s in Today’s Article?

• What is Happening to the Sun and How Hazardous are Solar Storms?
• What are the Observations Made by the ISRO About Solar Storm?
• Why were Auroras Visible from Ladakh?

What is Happening to the Sun and How Hazardous are Solar Storms?

• Currently, there are several magnetically active regions on the visible solar disk, producing multiple high-energy flares.
  • For example, a series of Coronal Mass Ejections (CMEs), emerged from AR13664 (currently an active region on the Sun), that hit the Earth recently.
  • CMEs are large ejections of magnetic particles and plasma from the Sun’s corona - the outermost part of its atmosphere.
• These continuous solar storms hold a strong potential for disturbing Space weather and causing major disturbances to the Earth’s magnetosphere.
• Intense solar storms can be harmful as they can interfere with and threaten the smooth operations of satellites operating in the Low Earth Orbit/ LEO (an altitude ranging between 200-1,600km).
• The highly energetic particle environment created by these solar storms can also induce heating in the upper atmosphere.
• This increases the risk of radiation hazards, causing a drag effect/ friction on satellites positioned at LEO, which in extreme cases can ignite and burn down the satellites.

What are the Observations Made by the ISRO About Solar Storm?

• Spacecraft OK:
  • Earth observation satellites including the 30 GEO spacecraft operated by ISRO were reported to be operating normally.
  • However, the increased atmospheric density caused by the solar event led to increased orbit decay, with some satellites experiencing 5-6 times higher decay.
    • Orbital decay is a gradual decrease of the distance between two orbiting bodies at their closest approach (the periapsis) over many orbital periods.
  • Also, ISRO’s navigation centre has not observed any significant decline in the NaVIC service
• Ground observations:
  • On 11 May daytime Total Electron Content (TEC) was high by about 10% with large variations indicating disturbed ionosphere.
  • TEC is the total number of electrons present along a path between a radio transmitter and receiver.
  • Radio waves are affected by the presence of electrons. The more electrons in the path of the radio wave, the more the radio signal will be affected.
• Aditya-L1 observations:
  • Aditya-L1 spacecraft recorded high-speed solar wind, high-temperature plasma, and energetic ion flux associated with the CMEs using its ASPEX payload.
  • The X-ray instruments on-board Aditya-L1 (SoLEXS and HEL1OS) also captured the powerful X-class flares, while the magnetometer detected changes in the interplanetary magnetic field.
• Chandrayaan-2 observations:
  • Chandrayaan-2 orbiter’s X-ray Monitor (XSM) observed many interesting phenomena associated with a geomagnetic storm.
  • It captured solar X-ray flux, autonomously identified large solar flares, and monitored the local high-energy particle environment.

Why were Auroras Visible from Ladakh?

• It has to do with increased space solar flare activity.
  • Solar physicists at the IISER (Kolkata) said that at least four strong solar storms arrived over Earth between 10- 11 May. The source of these storms was CMEs.
• Travelling at 700 km/s (close to the Earth’s atmosphere) and at a speed of 815 km/s (when they hit the Earth), the intensity of these incoming solar storms (most intense since 2003)was much higher than average.
• One of the manifestations of the solar storm’s interactions with the Earth’s atmosphere was the emergence of auroras in red, violet and blue colours.
• So strong were the storms that the aurora lights were visible from many lower-latitude regions.