54 research outputs found
Auroral imaging with combined Suomi 100 nanosatellite and ground-based observations: A case study
Auroras can be regarded as the most fascinating manifestation of space
weather and they are continuously observed by ground-based and, nowadays more
and more, also by space-based measurements. Investigations of auroras and
geospace comprise the main research goals of the Suomi 100 nanosatellite, the
first Finnish space research satellite, which has been measuring the Earth's
ionosphere since its launch on Dec. 3, 2018. In this work, we present a case
study where the satellite's camera observations of an aurora over Northern
Europe are combined with ground-based observations of the same event. The
analyzed image is, to the authors' best knowledge, the first auroral image ever
taken by a cubesat. Our data analysis shows that a satellite vantage point
provides complementary, novel information of such phenomena. The 3D auroral
location reconstruction of the analyzed auroral event demonstrates how
information from a 2D image can be used to provide location information of
auroras under study. The location modelling also suggests that the Earth's limb
direction, which was the case in the analyzed image, is an ideal direction to
observe faint auroras. Although imaging on a small satellite has some large
disadvantages compared with ground-based imaging (the camera cannot be
repaired, a fast moving spinning satellite), the data analysis and modelling
demonstrate how even a small 1-Unit (size: 10 cm x 10 cm x 10 cm) CubeSat and
its camera, build using cheap commercial off-the-shelf components, can open new
possibilities for auroral research, especially, when its measurements are
combined with ground-based observations.Comment: Accepted manuscript 34 pages, 17 figure
RAE2015 of the University of Turku: Bibliometric analysis for the University of Turku 2010-2013: Part 1
RAE2015 of the University of Turku: Bibliometric analysis for the University of Turku 2010-2013: Part 2
Auroral precipitation fading before and at substorm onset: ionospheric and geostationary signatures
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Ground-based and satellite observations of high-latitude auroral activity in the dusk sector of the auroral oval
On 7 December 2000, during 13:30-15:30 UT the MIRACLE all-sky camera at Ny Alesund observed auroras at high-latitudes (MLAT similar to 76) simultaneously when the Cluster spacecraft were skimming the magnetopause in the same MLT sector (at similar to 16:00-18:00 MLT). The location of the auroras (near the ionospheric convection reversal boundary) and the clear correlation between their dynamics and IMF variations suggests their close relationship with R1 currents. Consequently, we can assume that the Cluster spacecraft were making observations in the magnetospheric region associated with the auroras, although exact magnetic conjugacy between the ground-based and satellite observations did not exist. The solar wind variations appeared to control both the behaviour of the auroras and the magnetopause dynamics. Auroral structures were observed at Ny Alesund especially during periods of negative IMF B-Z. In addition, the Cluster spacecraft experienced periodic (T similar to 4 - 6 min) encounters between magnetospheric and magnetosheath plasmas. These undulations of the boundary can be interpreted as a consequence of tailward propagating magnetopause surface waves. Simultaneous dusk sector ground-based observations show weak, but discernible magnetic pulsations (Pc 5) and occasionally periodic variations (T - 2 - 3 min) in the high-latitude auroras. In the dusk sector, Pc 5 activity was stronger and had characteristics that were consistent with a field line resonance type of activity. When IMF BZ stayed positive for a longer period, the auroras were dimmer and the spacecraft stayed at the outer edge of the magnetopause where they observed electromagnetic pulsations with T similar to 1 min. We find these observations interesting especially from the viewpoint of previously presented studies relating poleward-moving high-latitude auroras with pulsation activity and MHD waves propagating at the magnetospheric boundary layers
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