How the interplanetary magnetic field affects the magnetic field line geometry in Earth’s magnetotail: statistical Cluster observations
Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
The effect of the IMF y-component to the geomagnetic field geometry down- wind from the Earth in the magnetotail was examined. Nine years of Cluster satellite data (2001-2009) were used to construct statistical averages of the magnetic field line geometry in the magnetotail between -20 and -10 Earth radii (rE ) in 5 cross sectional ”slices”. For each cross-section, all the data (the background) were plotted as well as separately data belonging to only time periods during which the IMF By was either positive or negative. The latter were plotted both without and with the removal of the background. It was found that the IMF By induces a collinear By component into the magnetotail, leading to twisting of the closed field lined. The induced By is constrained approximately to a band around the neutral sheet. The induction is most prominent on the flanks but equal out as the distance to the Earth increases. The positions of the nodes that connect the closed field lines within the tail, however, were found to change position asymmetrically to the side depending on the sign of the IMF By. Also, the rotation of the neutral sheet due to the IMF By was examined but no statistically significant rotation could be found.
The results clearly demonstrate that the IMF By has a significant effect on the magnetic field in the Earth’s magnetotail. The statistical approach introduced in this thesis of using several cross sectional slices will be exploited in the future studies of the IMF By effects to the night side geospace magnetotail.
Place, publisher, year, edition, pages
2016. , 37 p.
plasma, magnetosphere, solar wind, magnetic, field, line, geometry, CLUSTER, spacecraft
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:umu:diva-125478OAI: oai:DiVA.org:umu-125478DiVA: diva2:968812
Subject / course
Fysik C - Examensarbete
Bachelor of Science in Physics and Applied Mathematics
2016-06-01, Umeå, 19:45 (English)
Pitkänen, Timo, Forskare
Hamrin, Maria, Lektor