Energetic Oxygen Ions Found in Jupiter's Inner Radiation Belts Could Reveal the Role of the Planet's Moons on Ion Sources

In the Solar System, only Earth, Jupiter, and Saturn have their own magnetic fields surrounded by radiation belts, which are composed of fast-moving charged particles like electrons, protons, and heavy ions.

High velocities of these particles that could reach the speed of light could ionize other molecules upon their collision that would lead to the creation of hazardous environments dangerous for space probes and other scientific instruments. Among the three planets, Jupiter hosts the most hazardous radiation belts in the Solar System.

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Energetic Oxygen Ions Found in Jupiter's Inner Radiation Belts Could Reveal the Role of the Planet's Moons on Ion Sources

The Most Comprehensive Study of Jupiter's Inner Radiation Belt

In the study, titled "A Source of Very Energetic Oxygen Located in Jupiter's Inner Radiation Belts," published in Science Advances, the team of international researchers presented the most comprehensive study of inner radiation belt of Jupiter.

Their study showed that it is important to resolve the details of the undetermined mix of heavy ions because it could help in determining the role that the moons of Jupiter play relative to other less explored high-energy ion sources. Most of the high-energy ions in the radiation belts of Earth and Saturn came from atmospheric and ring interactions with external cosmic rays, but Jupiter's magnetosphere powers oxygen ions internally.

EurekAlert! reported that the radiation belt of the massive magnetic field of Jupiter extends several million kilometers into space, even reaching the moon's orbit of Europa that is 670,000 kilometers away from its gas giant planet. So far, three space missions have ventured into these innermost parts of Jupiter's radiation belts and performed measurements.

The Galileo spacecraft by NASA reached the inner radiation belt of Jupiter in 1995 and stayed for eight years to provide fundamental insights into the distribution dynamics of charged particles surrounding the gas giant planet. The Galileo spacecraft ventured into the innermost region within the orbits of Jupiter's moons Amalthea and Thebe.

Researchers said that they expected the measurement data coming from the inner region of the radiation belt would be heavily corrupted since neither of its two scientific instruments was built to operate in harsh conditions.

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Identifying Ion Composition in Jupiter's Inner Radiation Belt for the First Time

The authors of the current study used the scientific data from the missions that successfully entered the innermost region of Jupiter's radiation belt to study its ion composition, according to a similar report in Phys.org. For the first time, they were able to determine the ions in the radiation belts, their velocities, and spatial distribution.

They found that the area is dominated by high-energy oxygen ions, unlike the radiation belts of Earth and Saturn that are dominated by protons. Also, the region within the orbit of the moon Io contains high amounts of oxygen and sulfur ions.

According to the Laboratory for Atmospheric and Space Physics of the University of Colorado at Boulder, Io is the closest orbiting moon of Jupiter and is the most volcanically active moon in the Solar System, spring sulfurous material up to 500 km into the air that can be ejected into space. Electrons from these particles were stripped off, creating ions when they interact with the magnetic field of Jupiter.

Researchers of the new study said the distribution of heavy ions suggests that they likely came from a more distant region of the radiation belts. On the other hand, scientists also observed an increased concentration of oxygen ions in Amalthea's orbit, which could mean that there is another ion source in the innermost radiation belts.