| Summary: | Saturn has the second strongest magnetic field among the planets of the solar system, creating the second biggest magnetosphere, after Jupiter. The magnetosphere is similar to Earth's, as both of them are created by a dipole magnetic field, produced by a planetary dynamo. Despite the similarities, they have some major differences. First, the Kronian inner magnetosphere is being controlled by the fast rotation of the planet, while the Earth’s is being affected majorly by the solar wind. Second, a major Kronian magnetospheric plasma sources are the icy moons and the dusty rings, that are located within the inner magnetosphere, while Earth’s plasma sources are mainly the upper atmosphere and the solar wind. Since Cassini’s arrival at Saturn in 2004, more than ten years of data are collected, thus the magnetosphere and the plasma characteristics have been studied thoroughly. Persoon et al. [2013] made an electron density model, based on the electron density obtained by the upper hybrid resonance frequency (fUHR). The model is consistent with Enceladus as the electron plasma source –hence the denser plasma area is around the moon– and it describes the centrifugally drift of the plasma towards the magnetotail. The model is consistent with Cassini’s discovery that Enceladus expels water vapor and ice grains from the gazers located at its South pole, forming a plume. However, individual orbits data are not in agreement with the model, as the plasma density continues to increase toward the planet, which could be an indicator that there is an additional significant plasma source inside 4RS [Persoon et al., 2015]. Unfortunately, the fUHR is hard to be identified inside ~3RS where the magnetic field becomes stronger, and therefore, the electron plasma characteristics within that region are still unknown. This study is using the electron density data obtained by the Cassini's Langmuir Probe (LP). The LP is the ideal instrument to measure the cold plasma properties. Also, up to 2015, Cassini provided us with many orbits close ...
|
|---|