Saturn’s radio broadcasters mapped in 3-d for the first time
Observations from NASA’s Cassini spacecraft have been used to build, for the first time, a 3-D picture of the sources of intense radio emissions in Saturn’s magnetic field, known as the Saturn Kilometric Radiation (SKR).
The results will be presented by Dr Baptist Cecconi, of LESIA, Observatoire de Paris, at the European Planetary Science Congress on Tuesday 23rd September.
The SKR radio emissions are generated by high-energy electrons spiralling around magnetic field lines threaded through Saturn’s auroras. Previous Cassini observations have shown that the SKR is closely correlated with the intensity of Saturn’s UV aurora and the pressure of the solar wind.
The measurements were made using Cassini’s Radio and Plasma Wave Science (RPWS) experiment.
“The animation shows radio sources clustered around curving magnetic field lines. Because the radio signals are beamed out from the source in a cone-shape, we can only detect the sources as Cassini flies through the cone. When Cassini flies at high altitudes over the ring planes, we see the sources clearly clustered around one or two field lines. However, at low latitudes we get more refraction and so the sources appear to be scattered,” said Dr Cecconi.
The model found that the active magnetic field lines could be traced back to near-polar latitudes degrees in both the northern and southern hemisphere. This matches well with the location of Saturn’s UV aurora.
“For the purposes of the model, we’ve imagined a screen that cuts through the middle of Saturn, set up at right-angles to the line between Cassini and the centre of the planet. We’ve mapped the footprints of the radio sources projected onto the screen, which tilts as Cassini moves along its orbital path and its orientation with respect to Saturn changes. We’ve also traced the footprints of the magnetic field lines back to the cloud tops of Saturn,” said Dr Cecconi.
Although there were some minor differences between emissions in the northern and southern hemispheres, the emissions were strongest in the western part of Saturn’s sunlit hemisphere. This area corresponds to a region of Saturn’s magnetopause where electrons are thought to be accelerated by the interaction of the solar wind and Saturn’s magnetic field.
The observations were made over a 24-hour period during Cassini’s flyby of Saturn on 25-26th September 2006. This flyby was chosen because Cassini would approach from the southern hemisphere and swoop out from the northern hemisphere, allowing the instruments to take measurements from about 30 degrees below to about 30 degrees above the equatorial plane.
Anita Heward | alfa
The most recent press releases about innovation >>>
Die letzten 5 Focus-News des innovations-reports im Überblick:
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...