A new radiation belt of energetic protons between Saturn and its rings was discovered by team of researchers led by Greek scientist Elias Roussos as corresponding author, based on an analysis of the initial data from the final phase of exploration by the spacecraft Cassini.
In addition to Roussos, participants in the study included the Office of Space Research and Technology of the Academy of Athens and the team led by Professor Stamatis Krimigis, another notable Greek space exploration scientist. The paper presents the discovery of a new belt of proton radiation that has formed at a very short distance from the planet, limited by the atmosphere at its inner edge and the D-ring at its outer boundary, while it is almost completed isolated from the rest of Saturn's magnetosphere.
The discovery was presented in the journal "Science" along with other articles on the first results of the final phase of the Cassini mission. Cassini, after travelling for 13 years in space, completed its mission on 15 September 2017 with a spectacular 'suicide dive' into Saturn's dense atmosphere.
Saturn's magnetic field is over 10 times stronger nearer to the planet than outside its rings. This makes the trapping of protons so effective that they remain trapped in the same area for many years, constantly interacting with the D-ring and Saturn's atmosphere until they lose all their energy. However, the rate of this energy loss was, until recently, unknown because the quantity of the material in the faint D-ring was also unknown.
"A small quantity of dust in the D-ring would allow very intense particle radiation to develop that would create a problem for Cassini," said Dr. Nick Sergis, a scientific associate of the Office of Space Research that also contributed to the scientific paper, talking to the Athens-Macedonian News Agency. "The opposite, namely a dense D-ring that would absorb the protons quickly, would not allow the creation of such a belt," Sergis said.
The observation of the new radiation belt in Saturn adds to a series of discoveries made by the Cassini mission in which the MIMI experiment has contributed, with the participation of the Office of Space Research and Technology of the Academy of Athens.
"The MIMI team has published almost 200 articles in magazines and books in the last 14 years, 45 of them headed by Greek scientists of the team. These articles do not only refer to substantial discoveries about Saturn's magnetosphere but also its moons, its rings and even its heliosphere," stated Professor Stamatis Krimigis, head of the experiment and co-author of the article. "It is a huge achievement for a multinational team which is coordinated from the US but also has members in Germany, France and Greece," he added.