Geomagnetic storms and geomagnetic disturbances of the 23rd and 24th solar cycle

Postgraduate Thesis uoadl:2768767 326 Read counter

Unit:
Κατεύθυνση Αστροφυσική, Αστρονομία και Μηχανική (ΒΑΣΙΚΗ ΦΥΣΙΚΗ)
Library of the School of Science
Deposit date:
2018-06-12
Year:
2018
Author:
Alexakis Panagiotis-Chrysovalantis
Supervisors info:
Χριστοπούλου-Μαυρομιχαλάκη Ελένη, Ομότ.Καθηγήτρια, Τμήμα Φυσικής, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Δαγκλής Ιωάννης, Καθηγητής, Τμήμα Φυσικής, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Πρέκα-Παπαδήμα Παναγιώτα, Επίκ. Καθηγήτρια, Τμήμα Φυσικής, Εθνικό και Καποδιστριακό Πανεπιστήμιο Αθηνών
Original Title:
Γεωμαγνητικές καταιγίδες και γεωμαγνητικές διαταραχές του 23ου και 24ου ηλιακού κύκλου
Languages:
Greek
Translated title:
Geomagnetic storms and geomagnetic disturbances of the 23rd and 24th solar cycle
Summary:
Space Weather is the total of all processings and phenomena that occur in the area of Earth’s magnetosphere and around it. Most of these phenomena are born from processings that take place on the Sun and spread out to the interplanetary space, reaching the Earth and affect it’s magnetosphere with various effects on and in it. Geomagnetic storms are the most intense of these phenomena and are powerful disturbances of the Earth’s magnetosphere, both in its structure and in the intensity of its magnetic field. One effect is the influence on the satellite systems from these solar energetic structures and geomagnetic storms, with the result of malfunction or even destruction to the satellites’ systems, facts that can cause much both in economic and in operating terms (e.g. navigating systems).
In this dissertation a statistical study of all geomagnetic storms of the solar cycles 23 and 24 was performed with the usage of data from ground monitors of the geomagnetic indices Kp and Dst. The aim of the dissertation is to investigate the distribution of geomagnetic storms with the use of both geomagnetic indices and to compare the results. The number, intensity and time of occurrence of the occurred storms were recorded and a comparison between the two cycles was done, as well as a study of their monthly and annual distribution for both geomagnetic indices.
Specifically, 1030 geomagnetic storms were recorded with Kp index while with Dst index 523 storms were recorded. This implies that half of the geomagnetic storms that were recorded did not reach the Equator level but only reached the high latitudes. That is, with Kp index we also recorded the low intensity storms that did not have the necessary specifications to reach the Equator.
At the end, the results and the conclusions are being presented, as well as the prospects arising for further research and study of all the above issues. The main ones are:
a) The form of the storms distribution over the solar cycles, which seems to be slightly shifted to the solar cycles’ maximum by 1-2 years, but it is quite clear in its form and in its relation to the solar cycle.
b) The clear semiannual variation of geomagnetic activity, which shows us that geomagnetic activity is maximal at Equinoxes and minimal at Solstices (Russell and McPherron, 1973).
c) The occurrence of low geomagnetic activity at solar cycle 24 which confirms the low activity of this cycle (Jiang et al., 2015 ; Svalgaard Leif et al., 2005).

In the first chapter introductory concepts for the Sun, solar activity and interplanetary space are being given. In the second chapter we give the characteristics of the structure and plasma of the Earth’s magnetosphere. The third chapter deals with the pairing of Solar-Earth’s magnetosphere systems and refers to Space Weather, the geomagnetic indices used to describe it and its forecasting methods. The forth chapter presents the processing of geomagnetic storms’ data and the presentation of the results. Finally, in the fifth chapter we give the final conclusions of the processing, as well as the future prospects that appear from the results.
In the Appendix of this dissertation we refer the literature and related publications used throughout it, as well as the tables with all the geomagnetic storms recorded using the two geomagnetic indices.
Main subject category:
Science
Keywords:
Geomagnetic storms, solar cycle, space weather, geomagnetic indices, semiannual variation
Index:
No
Number of index pages:
0
Contains images:
Yes
Number of references:
48
Number of pages:
182
ΑΛΕΞΑΚΗΣ_ΠΑΝΑΓΙΩΤΗΣ_ΔΙΠΛΩΜΑΤΙΚΗ_ΕΡΓΑΣΙΑ.pdf (9 MB) Open in new window