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Session: Heliophysics and the Solar System

Name: Ms. Konstantina Moutsouroufi (National & Kapodistrian Univ. of Athens)
Coauthors: Sergis Nick (HSC)
Daglis Ioannis (UOA; HSC)
Achilleos Nicholas (University College London)
Type: Oral
Title: A Magnetospheric Stress Index: Construction and application to Saturn magnetosphere using long-term Cassini measurements.
Abstract:

A planet’s magnetosphere is being shaped by the forces applied to it, both externally and internally. Α magnetosphere strained by changes in external or internal pressures, correspondingly results in deformation of its magnetic field lines in almost all of its range. In order to study the dynamic changes in Saturn’s magnetosphere, it is useful to have a quantitative measure of its average stress, which can be compared to the measured fluctuations during a spacecraft’s individual passes. The most extensive and detailed field-and-particle measurements of the Saturn system were provided by the Cassini mission, and have expanded our understanding of the planet’s magnetosphere. In the present study we introduce and calculate a Magnetospheric Stress Index using measurements of Saturn’s magnetic field, obtained throughout the Cassini mission (2004-2017) near the equatorial plane of the magnetosphere, between 4 and 8 planet radii (RS), expanding previous works. The proposed index is similar to indices that have been developed to monitor the Earth’s and Jupiter’s magnetospheric stresses. The index indicates any unusual deviations from the average magnetospheric conditions and distinguishes them from smaller deviations expected due to usual fluctuations in the solar wind. Hence, the proposed index depicts the temporal magnetospheric deformation, despite the limitation of single-spacecraft measurements, and the lack of magnetopause monitoring.