Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
The Master's thesis is part of a more comprehensive research topic aimed at investigating
the interaction between the magnetosphere and the ionosphere. The study of the
temporal variation of the eld aligned currents in the auroral region was done through
analyzing Electric and Magnetic eld data downloaded from the ESA Cluster Active
Archive and gathered through in situ measurements by the tetrahedral Cluster satellite
constellation. The four satellites have an almost identical orbit, with a distance separation
ranging between a hundred kilometers to several thousand kilometers. This allows
for the measurement of the Electric and Magnetic elds associated with Birkeland currents
in the same spatial region at four dierent times. By performing a cross-correlation
between any two spacecraft measurements we obtain six correlation coecients along
with the corresponding time lags, which can then be used to study the lifetime of the
associated eld aligned currents. Further data analysis and interpretation is then performed
to obtain a better understanding of the temporal stability of auroral structures
and the intrinsic coupling between the ionosphere and the magnetosphere.
2015. , 67 p.