Magnetospheric Stress Index: Construction and application to the Kronian magnetosphere using long-term Cassini measurements

Postgraduate Thesis uoadl:2781178 358 Read counter

Unit:
Κατεύθυνση Αστροφυσική, Αστρονομία και Μηχανική (ΒΑΣΙΚΗ ΦΥΣΙΚΗ)
Library of the School of Science
Deposit date:
2018-09-10
Year:
2018
Author:
Moutsouroufi Konstantina
Supervisors info:
Ιωάννης Δαγκλής, Καθηγητής, Τμήμα Φυσικής, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Παναγιώτα Πρέκα - Παπαδήμα, Επίκουρη Καθηγήτρια, Τμήμα Φυσικής, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Γεώργιος Μπαλάσης, Κύριος Ερευνητής, Εθνικό Αστεροσκοπείο Αθηνών
Original Title:
Δείκτης Μαγνητοσφαιρικής Παραμόρφωσης: Μέθοδοι υπολογισμού και εφαρμογή στη μαγνητόσφαιρα του Κρόνου με τη χρήση μετρήσεων του διαστημοπλοίου Cassini
Languages:
Greek
Translated title:
Magnetospheric Stress Index: Construction and application to the Kronian magnetosphere using long-term Cassini measurements
Summary:
A planet’s magnetosphere is being shaped by the forces applied to it, both externally and internally. The most extensive and detailed measurements on Saturn’s systems were provided by the Cassini mission and have expanded our understanding of the planets’ magnetosphere. When a magnetosphere is being stressed by changes in external or internal pressures, its magnetic field lines are correspondingly being deformed 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 stress, which can be implemented by first calculating its ground state, and subsequently compare it to measurements obtained during individual passes.
In the present study we introduce and calculate a Magnetospheric Stress Index using measurements of Saturn’s magnetic field by the Cassini spacecraft, obtained throughout the mission (2004-2017) in the equatorial plane of the magnetosphere, between 4 to 8 planet radii (Rs). The proposed index is similar to indices that have been developed to monitor the Earth’s and Jupiter’s magnetospheric stresses. The index detects magnetosphere’s unusual deviations from the ground state and distinguishes them from smaller deviations that are consistent with the size and duration of expected, because of the usual fluctuations in the solar wind. Hence, index calculation/value along the spacecraft's track depicts the present magnetospheric deformation, despite the limitation of having measurements only by a single spacecraft, usually far from magnetopause. Moreover, the index value (and thus the overall system conditions), enables better assessment and interpretation of in-situ measurements and locally observed phenomena.
Main subject category:
Science
Keywords:
Saturn, magnetosphere, Magnetospheric Stress Index, Cassini spacecraft
Index:
No
Number of index pages:
0
Contains images:
Yes
Number of references:
29
Number of pages:
100
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