Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 1.490 IF 1.490
  • IF 5-year value: 1.445 IF 5-year
    1.445
  • CiteScore value: 2.9 CiteScore
    2.9
  • SNIP value: 0.789 SNIP 0.789
  • IPP value: 1.48 IPP 1.48
  • SJR value: 0.74 SJR 0.74
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 88 Scimago H
    index 88
  • h5-index value: 21 h5-index 21
Volume 29, issue 1
Ann. Geophys., 29, 167–179, 2011
https://doi.org/10.5194/angeo-29-167-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Ann. Geophys., 29, 167–179, 2011
https://doi.org/10.5194/angeo-29-167-2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.

  14 Jan 2011

14 Jan 2011

On large plasmoid formation in a global magnetohydrodynamic simulation

I. Honkonen1,2, M. Palmroth1, T. I. Pulkkinen1,*, P. Janhunen1, and A. Aikio3 I. Honkonen et al.
  • 1Finnish Meteorological Institute, Helsinki, Finland
  • 2Department of Physics, University of Helsinki, Helsinki, Finland
  • 3Department of Physical Sciences, University of Oulu, Oulu, Finland
  • *currently at: School of Electrical Engineering, Aalto University, Finland

Abstract. We investigate plasmoid formation in the magnetotail using the global magnetohydrodynamic (MHD) simulation GUMICS-4. Here a plasmoid implies a major reconfiguration of the magnetotail where a part of the tail plasma sheet is ejected downstream, in contrast to small Earthward-propagating plasmoids. We define a plasmoid based solely on the structure of the closed (connected to the Earth at both ends) magnetic field line region. In this definition a plasmoid is partly separated from the ordinary closed field line region by lobe field lines or interplanetary field lines resulting from lobe reconnection. We simulate an event that occurred on 18 February 2004 during which four intensifications of the auroral electroject (AE) index occurred in 8 h. Plasmoids form in the simulation for two of the four AE intensifications. Each plasmoid forms as a result of two consecutive large and fast rotations of the interplanetary magnetic field (IMF). In both cases the IMF rotates 180 degrees at 10 degrees per minute, first from southward to northward and some 15 min later from northward to southward. The other two AE intencifications however are not associated with a plasmoid formation. A plasmoid does not form if either the IMF rotation speed or the angular change of the rotation are small. We also present an operational definition for these fully connected plasmoids that enables their automatic detection in simulations. Finally, we show mappings of the plasmoid footpoints in the ionosphere, where they perturb the polar cap boundary in both hemispheres.

Publications Copernicus
Download
Citation