Holes in sun’s atmosphere can help predict space weather on Earth
Coronal holes are cooler, darker regions in the Sun’s upper atmosphere, the corona, from which high-velocity solar wind gushes into space. A new study has now found that the magnetic properties of these holes can be used to predict the severity of geomagnetic storms hitting Earth.
Geomagnetic storms occur when they erupt solar windStreams of magnetized particles from the corona interact with The Earth’s magnetic field and penetrate the atmosphere of the planet. Some geomagnetic storms are the result of coronal mass ejections (CMEs), powerful eruptions of plasma from the corona that usually originate sunspots.
Like coronal holes, sunspots are darker and cooler than the rest of the sun’s disk, but they form in the sun’s lower layer atmosphere of the sun, the photosphere. Unlike coronal holes, sunspots are areas where the Sun’s magnetic field is extremely strong and the magnetic lines are twisted. Eventually, the tangled magnetic lines burst, releasing a flash of light in the shape of a solar flare and a CME. In contrast, coronal holes have magnetic lines that are open and do not recede The sunallowing the solar wind to flow freely into space.
The new study found that the solar wind emanating from the coronal holes maintains its magnetic polarity 80% of the time during its journey through space. Knowing this polarity is key to predicting whether and how much the burst of solar wind will destabilize Earth’s magnetosphere.
Related: Huge solar flares erupt on the Sun from a “hyperactive” sunspot
When the Earth’s magnetic fields and that carried by the solar wind hit the same poles, they repel each other and have very little effect on the planet. However, when these fields meet through their opposite poles, they combine, allowing the solar wind’s charged particles to penetrate deep into Earth’s atmosphere. As these solar wind particles interact with the air around the planet, they trigger beautiful ones Aurora shows spreading around the poles.
However, these magnetic interactions also have many undesirable side effects. In extreme cases, they can lead to this power outages on Earth, damage or even cause orbiting satellites fall out of orbit.
Currently, space weather Forecasters will have to wait for the solar wind to match NASA’s SOHO satellites to learn more about the magnetic properties of the solar wind. SOHO orbits the Sun synchronously with the Earth, positioned in the so-called Lagrange point 1 (L1) 900,000 miles (1.5 million kilometers) from Earth toward the Sun. It takes several days for the solar wind to reach SOHO. But it only takes a few hours before it arrives on Earth.
The new prediction method, developed by a team of researchers from the Skolkovo Institute of Science and Technology in Russia, the University of Graz in Austria, the Leibniz Institute for Astrophysics in Germany and the University of Zagreb in Croatia, could extend these warning times by hours to days the kind of solar wind flares that come out of coronal holes.
“We have shown that the magnetic field of a coronal hole propagating from the Sun to Earth is conserved more than 80% of the time,” said Simona Nitti, a science graduate from Skolkovo and the study’s lead author, in a per E -Mail sent statement. “This opens up the possibility of using the magnetic field derived from solar observations instead of the magnetic field of L1.”
A single coronal hole can cause quite a bit of trouble. As the sun rotates, an old coronal hole can reappear after 27 days. Some coronal holes have historically managed to survive for up to six months, spewing solar wind at Earth with each and every passage across the Sun’s visible disc.
The study (opens in new tab) was published in the Monthly Notices of the Royal Astronomical Society on January 5.
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