Multi-instrumental auroral case studies at substorm conditions
|Danielides, Michael A.1
1University of Oulu, Faculty of Science, Department of Physical Sciences
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|Academic Dissertation to be presented with the assent of the Faculty of Science, University of Oulu, for public discussion in the Auditorium L10, Linnanmaa, on September 30th, 2005, at 12 o’clock noon.
Professor Hannu Koskinen
Professor Vyatseslav A. Pilipenko
The general aim of the present study is to gain insight into physical mechanisms of some auroral forms on the basis of multi-instrumental measurements (satellites, rockets and ground-based magnetic and riometer instruments) in the vicinity of the auroras observed by ground-based all-sky cameras.
One part of this work is related to the Auroral Turbulence II sounding rocket experiment. It was launched on February 11th, 1997, at 08:36 UT from Poker Flat Research Range, Alaska, into a moderately active auroral region after a substorm onset. This unique three-payload rocket experiment contained both electric and magnetic in the evening sector (21 MLT), auroral forms at the substorm recovery were investigated, providing details of the quiet and disturbed auroral densities and DC electric patches propagating along them like a luminosity wave. Those evening auroral patches and associated electric fields formed a 200-km spatially-periodic structure along the arc, which propagated westward at a velocity of 3 km s-1.
The other part of this study describes ground signatures of dynamic substorm features observed by the IRIS imaging riometer, magnetometers and all-sky camera during late evening hours. The magnetometer data were consistent with the motion of upward data are used to estimate the intensity of FAC associated with these local current-carrying the excitation of the low-frequency turbulence in the upper ionosphere. As a result, a quasi-oscillating regime of anomalous resistivity on the auroral field lines can give rise to the burst-like electron acceleration responsible for simultaneously observed auroral forms and bursts of Pi1B pulsations.
Report series in physical sciences
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