The magnetic shield of the Earth vibrates like a drum when it is hit by strong external impulses and, in fact, behaves like that musical instrument when emitting a certain wave pattern, according to a study published today by the journal Nature. The research, developed by Queen Mary University in London, has detected for the first time this effect, which had only been described theoretically 45 years ago.
To verify its existence, the experts analyzed data provided by five satellites of the THEMIS mission, launched by NASA in 2007 to study the northern lights and, in this case, observed the impact of a "strong plasma jet" on the part more exterior of the shield, also known as magnetopause.
This area, the researchers explain, is the border between the Earth's magnetic field and interplanetary space dominated by the solar wind, which protects Earth from many of the radiations present in space. When that strong impulse strikes the magnetopause, they point ripples that run its surface and that, in turn, are reflected back as they approach the magnetic poles.
The interference created between the original waves and the reflected ones generates a standing wave pattern, in which certain points appear to be fixed while others vibrate back and forth. The surface of a drum, stand out, behaves in this same way when it receives an impact of that type. "It has been speculated whether these vibrations similar to those of the drums occurred or not, given the lack of evidence that has been since it was proposed 45 years ago. Another possibility is that it was too difficult to detect them, "Martin Archer, the lead author of the study, recalls in a statement.
The magnetic shield, he continues, is "continuously affected by turbulence", So the observation of the" drum effect "on the magnetopause required the unique and directed impact of the" strong plasma jet ". "We also needed to place many satellites in the right places during the event in order to discard other sounds or resonances. The event described in this study fulfilled all the requirements and, finally, we have shown its natural response ", celebrates Archer.
The knowledge about the movements of the magnetopause, he concludes, are important to control the flow of energy within our space environment, as they also influence space weather, with consequences for our technology, such as power grids, airlines and positioning systems global.