NASA's Global-scale Observations of the Limb and Disk (GOLD) mission has identified unexpected X and C-shaped structures within Earth's ionosphere. The ionosphere, a layer of charged particles in the upper atmosphere, plays a critical role in facilitating long-distance radio communication.
Sunlight ionization typically governs the ionosphere's density, causing it to fluctuate throughout the day. GOLD, a geostationary satellite launched in 2018, specifically monitors these variations. It recently observed the formation of unusual X-shaped patterns within typically smooth plasma regions in the ionosphere.
Previously, scientists observed these X-shapes forming during periods of heightened space weather activity, such as solar storms or volcanic eruptions. However, GOLD's detection of these structures during geomagnetically quiet times suggests additional, yet unidentified, factors influencing the ionosphere's dynamics.
"Earlier reports of merging were only during geomagnetically disturbed conditions," Fazlul Laskar, a research scientist at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP), said in a statement. Mr Laskar is the lead author of a paper published in April in the Journal of Geophysical Research: Space Physics that described these unexpected observations.
"It is an unexpected feature during geomagnetic quiet conditions," he said.
This indicates that events in the lower atmosphere have a greater impact on the ionosphere than extreme solar or volcanic activities.
Besides the unusual X shapes, GOLD also detected curved C-shaped bubbles in the plasma, which appeared surprisingly close together. Scientists believe these bubbles are shaped and oriented based on wind directions. However, GOLD captured images of C-shaped and reverse C-shaped bubbles as close as 400 miles (643 kilometers) apart. According to researchers, such drastic changes in wind patterns over short distances are highly unusual.
"It's really important to find out why this is happening," LASP research scientist Deepak Karan, lead author of a separate paper published in November in the Journal of Geophysical Research: Space Physics, said in the statement. "If a vortex or a very strong shear in the plasma has happened, this will completely distort the plasma over that region. Signals will be lost completely with a strong disturbance like this."
This is not NASA's first attempt to study the ionosphere. Recently, the Atmospheric Perturbations Around The Eclipse Path (APEP) project explored how reductions in sunlight and temperature impact Earth's upper atmosphere. During the annular solar eclipse on October 14 across the southwest U.S. and the total solar eclipse on April 8 across North America, NASA launched three suborbital sounding rockets into the eclipse path to measure changes in electric and magnetic fields, as well as density and temperature within the ionosphere. The results of this mission are still pending.
