Huge ‘belts’ light speed around the Earth, and now we know how fast they spread


When you look at the sky, the field of space around the earth may be as clear as a song, but there is a lot happening there, which we cannot see. In recent years, people studying radiation trapped by the Earth’s magnetic field have found something peculiar – electrons close to the speed of light.

This alone is not the peculiar part; Near-light-motion, or relativism, electrons are well known in the universe, amplified by cosmic particle accelerators. The strange thing was that sometimes the extra fast, ExtremeRelativistic electrons appear – but only during some solar storms, and not others.

A team of scientists led by space physicist Helle Allison of the GOZ German Center for Geoscience in Germany have just figured out why. And all this has to do with the invisible, particle-filled radiation belt around the Earth.

Researchers found that if a solar storm electrons can achieve those ultrarelativistic speeds before the plasma is significantly reduced in a radiation belt.

Officially known as the Van Allen Radiation Belt, these belts lie in space pockets almost immediately after Earth. The inner belt stretches from 640 to 9,600 kilometers (400 to 6,000 miles) in height, and the outer belt ranges from about 13,500 to 58,000 kilometers. They are the regions in which the Earth’s magnetic field webs charged particles from the solar wind.

Here on Earth, these areas will not particularly impact our day-to-day life (although we will certainly note that if they went away and the solar wind could freely melt us with charged particles), but space The planet immediately surrounds the planet, up to an altitude of about 2,000 kilometers, where we place most of our satellites. This is where it shows what space weather can produce.

When such high speeds are accelerated, these electrons become a threat. Because of their high energy, even the best shielding cannot keep them out, and their charge can destroy sensitive electronics when they enter a spacecraft.

So Allison and his team set about analyzing data from the Van Allen probe, a twin spacecraft launched in 2012 to study the Van Allen belts (before becoming dormant in 2019).

During this time, the investigation recorded several solar storms, intense events, including an outbreak from the Sun due to terrestrial magnetospheres with solar wind and radiation.

They wanted to find out why some of these storms resulted in ultralativistic electrons, and others did not. In particular, they wanted to examine plasma.

Plasma waves – fluctuations in electric and magnetic fields – are known to have a fast effect on electrons, which can “surf” like plasma waves that Wexfire uses to accelerate water waves.

And solar storms are known to excite plasma waves around the Earth; In fact, the Van Ellen probe contributed to the discovery that the so-called “chorus” plasma waves around the Earth could accelerate electrons, although the effect alone was considered insufficient to explain the observed ultralativistic electrons. Researchers thought that a two-way acceleration process would be taking place.

So the team compared the plasma observations taken by Van Allen with and without ultralightativistic electrons, in an attempt to find out what is happening.

Plasma density is difficult to measure directly, but the team was able to estimate density from electric and magnetic field fluctuations. And researchers found that ultratreativistic electrons correlated with an extreme decrease of plasma density and the presence of chorus waves.

This is a result that shows that the two-step acceleration process, as previously assumed responsible, is not necessary for ultralightivistic electrons.

Although the team focused on the most extreme electron motion, they also found that when the plasma density was low, the chorus waves accelerated the electrons acceleration speed to shorter timelines when the plasma density was higher.

“This study suggests that electrons in the Earth’s radiation belt can be accelerated locally to ultralightivistic energies, if the plasma environmental conditions – plasma waves and temporarily low plasma densities – are correct, “Is explained. And Potsdam University in Germany.

“Particles can be thought of as surfing plasma waves. In areas of extremely low plasma density they can take a lot of energy from plasma waves. Similar mechanisms may work in the magnetosphere of outer planets such as Jupiter or Saturn. . In other astrological objects. “

The research has been published in Science advance.

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