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EP: Fachverband Extraterrestrische Physik
EP 7: Solar-Terrestrische Beziehungen
EP 7.3: Talk
Tuesday, March 27, 2007, 17:00–17:15, H46
Determining orientation, thickness, and velocity for a 2D, non-planar magnetopause — •Adrian Blǎgǎu1,2, Berndt Klecker1, Götz Paschmann1, Manfred Scholer1, Stein Haaland1,3, Octav Marghitu2,1, and Elizabeth Lucek4 — 1Max-Planck-Institut für extraterrestrische Physik, Garching, Germany — 2Institute for Space Sciences, Bucharest, Romania — 3University of Bergen, Norway — 4Imperial College, London, UK
Since the Cluster mission became operational we benefit from correlated measurements taken simultaneously at four points in space. The differences in the position and time of the satellites' encounter with the terrestrial magnetopause (MP) can be used in a timing method to infer its orientation, thickness and velocity. This multi-spacecraft technique, which assumes a planar MP, proves reliable and offers an independent check for various single-spacecraft techniques. We will present a case when the techniques of Minimum Variance Analysis on the magnetic field (MVAB), and Minimum Faraday Residue (MFR) provide different individual MP normals, included approximately in the same plane. Such a configuration is not necessarily related to experimental errors, but can have natural causes like a local bulge/indentation in the MP or a large amplitude traveling wave on this surface. The timing technique yields a normal well apart from the single-spacecraft normals, indicating that the underlying planar assumption is questionable. We explain our case by considering a 2D, non-planar magnetopause and discuss the influence of such a geometry on the results based on MVAB, MFR and DeHoffmann-Teller techniques.