A very high-energy proton radiation band between Saturn and its dense rings discovered Greek scientists, analyzing the first results of the final phase of the Cassini spacecraft's mission .

The new study, which includes the Space Research Office of the Academy of Athens and the team of academic professor Stamatis Krimizis , describes the discovery of a new proton radiation band, formed at a close distance from the planet, coexisting with ring D and located in almost complete isolation from the rest of Saturn's magnetosphere .

The radiation band is created by the incidence of galactic cosmic radiation in the rings. The protons produced in this way then interact with Saturn's atmosphere, the dim ring D and the sub-rings of the D68 and D73.

The discovery was presented in the journal Science together with other articles by foreign scientists about the first scientific results of the final phase of the mission. On September 15, 2017 the Cassini completed, with an impressive 'suicide dive' in the dense atmosphere of Saturn, the research mission that lasted 13 years.

Earlier Cassini had passed 22 times between the rings and the surface of the giant planet. This area, which has been unexplored until then, also includes Ring D, the innermost and smoother of Saturn's rings.

Όταν το Cassini είχε εισέλθει σε τροχιά γύρω από τον Κρόνο τον Ιούλιο 2004, οι ανιχνευτές του επιστημονικού πειράματος MIMI (Magnetospheric IΜaging Instrument), που μετράει πολύ υψηλής ενέργειας φορτισμένα και ουδέτερα σωμάτια, εστίασε στην περιοχή μεταξύ του πλανήτη και του δακτυλίου D. Οι μετρήσεις «φωτογράφισαν» έναν πληθυσμό φορτισμένων σωματιδίων, η ακριβής σύσταση και ιδιότητες του οποίου ωστόσο παρέμειναν ασαφείς. Η μοναδική ευκαιρία να επαναληφθούν οι πρώτες μετρήσεις του 2004, παρουσιάσθηκε μετά τον Απρίλιο του 2017, αυτή τη φορά υπό καλύτερη γεωμετρία παρατήρησης.

"With Cassini approaching so close to Saturn, we were given the opportunity to observe the particles that might have formed the population that MIMI had 'photographed' in 2004, and other, much higher energy that we could not count from distance, "said study leader Dr. Elias Roussos from the Max Planck Institute for the Solar System Research in Göttingen , Germany.

The Saturn's magnetic field is more than ten times stronger near the planet than outside the rings. This makes proton trapping so effective that they remain locked in the same area for years, continuously interacting with D-ring and Saturn's atmosphere, until they lose all of their energy. However, the rate at which protons lose energy was unknown, mainly because the amount of material in the dim ring D was also unknown.

"A low amount of D-ring powder would allow huge volumes of particle radiation to develop, which could create a problem for Cassini ," Dr Atkinson said in a statement to the Athenian and Macedonian News Agency. Nikos Sergis , scientific associate of the Space Research and Technology Office and co-author of the article. "The opposite, a relatively dense D-ring that would quickly absorb the protons, would have the effect of not creating such a band," he added.

The measurements revealed a remarkable and steady accumulation of energy protons in a radiation band extending from the upper layers of the Saturn atmosphere and along the entire D ring. Although many of the protons that formed it had extremely high energies ten times higher than what MIMI expected to measure, particle radiation levels were not dangerous for Cassini .

Beyond ring D, the three rings A, B and C extend, which, due to their high density, are distinct in Saturn's photographs. These rings form an impenetrable obstacle with a radius of 62,000 kilometers, where the trapping of charged particles is prohibitive. This means that the new radiation band at Saturn could not extend beyond ring D, which MIMI 's measurements confirmed.

'The great efficiency of rings A-C to absorb charged particles create a band of radiation that is totally isolated from the rest, changeable magnetosphere Saturn "stated in the ANA-MPA Dr. Konstantinos Dilvas , associate of the Space Research and Technology Office and co-author of the article.

This isolation of the radiation band is a feature not found anywhere else in our solar system. This offers the possibility of examining a radiation band under almost "laboratory conditions", and this is because the mechanism of its creation is determined only by the influx of cosmic radiation into the Saturn system, a natural process that is unchanged over time. On Earth the conditions are much more complicated as there are no rings that could stop the unpredictable variable input of high energy particles from the Sun to our planet's radiation zones.

The observation of the new radiation zone in Saturn is added to the vast array of discoveries of the Cassini mission , which was supported by the MIMI experiment , with the participation of the Academy of Space Research and Technology of the Academy of Athens.

"The MIMI team has published nearly 200 articles in magazines and books over the past 14 years, 45 of which were headed by Greek team researchers. These articles are not only about major discoveries about Saturn 's magnetosphere , but also about its moons, rings, and the heliosphere, "said Professor S. Krimizis , head of the MIMI experiment and co-author of the article. "This is a huge achievement for a multinational group, coordinated by the US but including members from Germany, France and Greece," he added.