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An
illustration of solar flare impacts on the whole geospace. Credit: Jing Liu. |
The magnetosphere is a system of magnetic fields that surrounds the planet Earth. This massive, comet-shaped system deflects charged particles from the sun, protecting our planet from dangerous radiation and preventing solar wind (a stream of charged particles produced from the sun's upper atmosphere) from degrading the atmosphere.
While previous research has accumulated extensive evidence of
the effects of solar wind on Earth's magnetosphere, the influence of solar
flares (i.e., sudden eruptions of electromagnetic radiation on the sun) is yet
unknown. Solar flares are extremely powerful explosions that can last anywhere
from a few minutes to several hours and can be spotted using X-rays or optical
equipment.
Researchers
from China's Shandong University and the United States' National Center for
Atmospheric Research recently published a research on the effects of solar
flares on Earth's magnetosphere. Their work, which was published in Nature
Physics, provides fresh information that could lead to a better understanding
of geospace dynamics. The upper atmosphere, ionosphere (the ionised section of
the atmosphere), and magnetosphere are all part of geospace, which is the area
of outer space closest to Earth.
Professor
Jing Liu, one of the study's authors, explained, "The magnetosphere is
positioned above the ionosphere and is the totally ionized space region over
1000 km from the ground." "The region is encircled by the solar wind
and is influenced and controlled by the earth's magnetic field as well as the
magnetic field of the solar wind."
The
magnetosphere protects Earth from solar wind and other solar particles by
preventing them from accessing the planet's other protective layers.
Nonetheless, previous research has shown that magnetic lines from these two
locations can 'link" when the direction of solar wind is opposite that of
the magnetosphere's magnetic field. This means that certain solar wind
particles may be delivered directly to the space around Earth.
"We wondered if the flare process, which is marked by increased radiation, may damage not just the earth's ionosphere but also the magnetosphere, causing disturbances similar to the solar wind?" Liu remarked. "To solve this question, we used data from worldwide satellite navigation systems, the European incoherent scattering radar network, ionospheric satellites, lunar orbiting satellites, and other sources."
During a
solar flare occurrence on September 6, 2017, Liu and his colleagues reviewed
data acquired by various devices and satellites. They used a newly built
numerical geospace model developed at the National Center for Atmospheric
Research to accomplish this. The high spatial-temporal resolution magnetosphere
ionosphere thermosphere model (LTR) reproduces the changes in the
magnetosphere-ionosphere coupling system caused by solar flares.
The
researchers were able to uncover solar flare effects on magnetospheric dynamics
and the electrodynamic interaction between the magnetosphere and the ionosphere
using the LTR model and previously obtained data. At altitudes between 90 and
150 km, they found a rapid and substantial increase in flare-induced
photoionization of the polar ionospheric E-region. The event reported by Liu
and his colleagues appears to have a number of repercussions on the geospace
region, including lower Joule heating of the Earth's upper atmosphere,
reorganisation of magnetosphere convection, and variations in auroral
precipitation.
"Through electrodynamic coupling, we revealed that solar flare impacts extend throughout geospace and are not limited, as previously thought, to the atmospheric region where radiation energy is absorbed," Liu added. "Our research also provides new hints for researching and comprehending the consequences of solar flares on other planets because the solar-magnetosphere-ionosphere coupling process is comparable in other Earth-like worlds. In the future, I'd like to investigate the consequences of flares on planets with similar magnetospheres (such Jupiter, Venus, and Saturn)."
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