Earth Planets Space, Vol. 62 (No. 3), pp. 333-345, 2010
Anja Stadelmann1, Joachim Vogt2, Karl-Heinz Glassmeier1,3, May-Britt Kallenrode4, and Gerd-Hannes Voigt5
1Institut für Geophysik und extraterrestrische Physik, Technische Universität Braunschweig, Germany
2School of Engineering and Science, Jacobs University Bremen, Germany
3Max Planck Institut füur Sonnensystemforschung, Katlenburg-Lindau, Germany
4Fachbereich Physik, Universität Osnabrück, Germany
5Fachbereich 06, Luft- und Raumfahrttechnik, Fachhochschule Aachen, Germany
(Received April 6, 2009; Revised October 9, 2009; Accepted October 10, 2009; Online published March 4, 2010)
The geomagnetic field is part of the shield prohibiting energetic particles of solar and cosmic origin directly hitting the Earth surface. During geomagnetic polarity transitions the geomagnetic field strength significantly decreases with energetic particles having a much better access to the atmosphere and surface. To study in more detail the flux of energetic particles into the paleomagnetosphere we use a potential field approach to model the paleomagnetosphere which generalizes the parametric model of Voigt (1981) by taking into account a non-zero quadrupole moment of the core field. We study in particular the quadrupolar situation as a geomagnetic polarity transition is also characterized by a significant increase of non-dipolar contributions. Our model is used as a tool for tracing particle trajectories in such paleomagnetospheres and to assess variations of high-energy particle fluxes into the atmosphere. As a first application of the particle tracing scheme we determine cutoff latitudes and impact areas for different paleomagnetospheric configurations. For configurations with equivalent magnetic field strength or magnetic energy the impact area is very similar.
Key words: Geomagnetic field, polarity transition, paleomagnetosphere, cosmic rays, solar energetic particles.