Berlin 2005 – wissenschaftliches Programm

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EP: Extraterrestrische Physik

EP 1: Magnetosph
äre und Ionosph
äre

EP 1.7: Vortrag

Freitag, 4. März 2005, 11:30–11:45, TU BH349

Energy Conversion in the Auroral Magnetosphere — •Octav Marghitu^1,2, Maria Hamrin³, Berndt Klecker¹, Mats André⁴, Stephan Buchert⁴, James McFadden⁵, and Hans Vaith¹ — ¹Max-Planck-Institut für extraterrestrische Physik, Garching, Germany — ²Institute for Space Sciences, Bucharest, Romania — ³Physics Department, University of Umeå, Sweden — ⁴Swedish Institute of Space Physics, Uppsala, Sweden — ⁵Space Sciences Lab., University of California at Berkeley, USA

The energy dissipated in the auroral ionosphere is believed to come from generator regions located far away in the magnetosphere. Several studies have addressed the auroral generator by using analytical, semi-analytical, and numerical tools. However, in the literature there is a lack of observational investigations of the generator region; for example, to our knowledge, an analysis of the power density, E·J (with E the electric field and J the current density vector), is missing.

In this paper we examine conjugated night-side data from the four CLUSTER satellites (in the magnetotail, at an altitude of ∼20 R_E) and the FAST satellite (above the auroral oval, at ∼0.5 R_E). Because of its four simultaneous measuring points, CLUSTER makes possible the complete evaluation of J; in addition, we use estimates of E from two different instruments, which improves on the reliability of these data. At the same time FAST offers a ’snapshot’ over the electron precipitation and energy flux into the ionosphere.