The researchers found that the process they discovered could occur on other planets.
Jupiter has the most powerful auroras in the solar system, circling constantly above both of its poles. Since they only shine at invisible wavelengths, we cannot see them with the naked eye, which is why they were only discovered 40 years ago. Since then, scientists have wondered how these auroras cause periodic bursts of X-rays, Sciencealert reports.
Using data from the Juno spacecraft and the XMM-Newton space X-ray observatory, a team of scientists led by planetary scientist Zhonghua Yao of the Chinese Academy of Sciences has linked the X-ray bursts to fluctuations in the magnetic field lines of the gas giant.
These vibrations create waves in the plasma that propagate along the lines of force of the magnetic field, periodically causing heavy ions to enter and collide with Jupiter’s atmosphere, releasing energy in the form of X-rays.
“We saw Jupiter create X-rays for four decades, but we didn’t know how it happened. We only knew that they were formed when ions hit the planet’s atmosphere,” says astrophysicist William Dunn of University College London in the UK. …
“We now know that these ions are carried by waves of plasma – this explanation has not been offered before, despite the fact that a similar process causes the aurora on Earth. Therefore, it may be a universal phenomenon that is also present in other parts of the cosmos.”
On Earth, auroras are created by particles coming from the Sun. They collide with the Earth’s magnetic field, which sends charged particles such as protons and electrons along the magnetic field lines to the poles, where they travel into the Earth’s upper atmosphere and collide with atmospheric molecules. As a result, the ionization of these molecules creates an amazing radiant phenomenon.
But on Jupiter, everything happens a little differently. Auroras are a permanent and long-lasting phenomenon there. This is because the particles do not come from the Sun, but from Jupiter’s moon Io, the most volcanic world in the solar system. Io constantly spews sulfur dioxide, which is immediately removed due to the complex gravitational interaction with the planet, ionizes and forms a plasma envelope around Jupiter.
To figure out how the X-ray pulses are generated, the research team studied the planet using simultaneous observations of the Juno spacecraft and the XMM-Newton observatory for 26 hours. During this time, Jupiter was emitting X-rays approximately every 27 minutes.
Based on these observations, scientists have used computer simulations to determine how plasma and X-rays might be related.
Scientists have concluded that the compression of Jupiter’s magnetic field creates waves of oxygen and sulfur ions that spiral along the magnetic field lines to the poles of Jupiter, where they collide with the atmosphere and generate X-ray bursts.
These waves are called electromagnetic ion cyclotron waves, and they are also associated with the twinkling auroras here on Earth.
It is currently unclear what is causing the collapse of Jupiter’s magnetic field. This can be the influence of the solar wind, the circulation of heavy substances in the Jupiter magnetosphere, or surface waves at the magnetopause, the outer boundary between the magnetosphere and the surrounding plasma.
The fact that the same mechanism was associated with the appearance of auroras in two different worlds suggests that it may be quite common in the solar system as well as in the rest of the galaxy, scientists say.
“We have now identified this fundamental process and there is a lot of room for further study,” says Yao.
“Similar processes are likely going on around Saturn, Uranus, Neptune and possibly exoplanets, with different types of charged particles roaming the waves.”
The results of the study show that electromagnetic ion cyclotron waves may play an important, previously unnoticed role in the ionic functionality of Jupiter’s atmosphere and may help to better understand plasma processes in the galaxy, scientists say.
