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A new study revealed that the Earth's magnetic shield was beating like a drum when it was hit by external impulses. This confirms a decades-old theory
The Earth's magnetic field is driven by convection currents in the outer core of the Earth. Differences in temperature, pressure and composition in the outer core cause some parts of the core to move. The flow of this liquid iron generates electric currents, which in turn produce magnetic fields. The resulting magnetic fields generate additional electric currents, which then generate their own magnetic fields, etc. This self-sustaining natural loop is called a geodynamo and produces a magnetic field that revolves around the planet.
This magnetosphere is essential to life on Earth because it protects the atmosphere from the erosion of the solar wind and deflects cosmic rays (charged particles of energy that come mostly from outside the solar system). However, we still learn a lot about the magnetosphere. Obviously, no one has gone to downtown to see how it is formed and the measurements of its overall structure remain difficult. In a new article, researchers describe a feature of this area that was mathematically predicted 40 years ago but never seen before.
Basically, when an impulse strikes the outer limit of magnetopause, ripples can spreadrface. These then gand reflect when they approach the magnetic poles. It's a bit like how acoustic waves are absorbed and reflected by a drum. When the impulse interacts with the magnetosphere of the Earth, the interference caused by the waves causes the formation of a standing wave.rn In what specific points seem to remain motionless while others vibrate – this is exactly how a drum sounds when struck.
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Martin Archer, physicist of space at Queen Mary University in London and lead author of the article, explains:
"There has been speculation that these drum-like vibrations may not occur at all, given the lack of evidence over the past 45 years since they were proposed. Another possibility is that they are simply very difficult to detect permanently. "
"The Earth's magnetic shield is constantly shaken by turbulence, so we thought that a clear proof of the proposed expanding vibrations might require a violent shock. You would also need many satellites in the right places during this event to eliminate other known sounds or resonances. The event in the newspaper ticked all these fairly strict boxes and we finally showed the natural response of the border, "said Archer.
In order to prove this theory, the researchers used data from five NASATHEMIS satellites, specially designed to study the magnetosphere. These five satellites were ideally located when a powerful single plasma jet struck the magnetopause.
The probes were able to detect the oscillations of the boundary and the resulting sounds in the Earth's magnetic shield, which confirmed the battery model and excluded any alternative explanation.
The Earth is not the only one to have a magnetosphere. Other planets, such as Mercury, Jupiter and Saturn, also possess a similar magnetic shield, which means that vibrations similar to those of a drum may be possible elsewhere. However, further research is needed to understand how often these vibrations occur and what their significance is.
Movements of magnetopause can have far-reaching effects on space weather, causing potential damage to technologies such as power grids, GPS and even airlines.
Journal reference: 'Direct observations of a specific mode of surface of the magnetopause at the exit of the day'. Archer et al. Nature Communications.
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