A Magnetohydrodynamic Modeling of the Interchange Cycle for Oblique Northward Interplanetary Magnetic Field

Masakazu Watanabe, Shigeru Fujita, Takashi Tanaka, Yasubumi Kubota, Hiroyuki Shinagawa, Ken T. Murata

Research output: Contribution to journalArticle

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Abstract

We perform numerical modeling of the interchange cycle in the magnetosphere-ionosphere convection system for oblique northward interplanetary magnetic field (IMF). The interchange cycle results from the coupling of IMF-to-lobe reconnection and lobe-to-closed reconnection. Using a global magnetohydrodynamic simulation code, for an IMF clock angle of 20° (measured from due north), we successfully reproduced the following features of the interchange cycle. (1) In the ionosphere, for each hemisphere, there appears a reverse cell circulating exclusively in the closed field line region (the reciprocal cell). (2) The topology transition of the magnetic field along a streamline near the equatorial plane precisely represents the magnetic flux reciprocation during the interchange cycle. (3) Field-aligned electric fields on the interplanetary-open separatrix and on the open-closed separatrix are those that are consistent with IMF-to-lobe reconnection and lobe-to-closed reconnection, respectively. These three features prove the existence of the interchange cycle in the simulated magnetosphere-ionosphere system. We conclude that the interchange cycle does exist in the real solar wind-magnetosphere-ionosphere system. In addition, the simulation revealed that the reciprocal cell described above is not a direct projection of the diffusion region as predicted by the “vacuum” model in which diffusion is added a priori to the vacuum magnetic topology. Instead, the reciprocal cell is a consequence of the plasma convection system coupled to the so-called NBZ (“northward Bz”) field-aligned current system.

Original languageEnglish
Pages (from-to)272-286
Number of pages15
JournalJournal of Geophysical Research: Space Physics
Volume123
Issue number1
DOIs
Publication statusPublished - Jan 1 2018

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interplanetary magnetic fields
Interchanges
magnetic fields
Magnetohydrodynamics
magnetohydrodynamics
Ionosphere
Magnetic fields
magnetic field
ionosphere
Magnetosphere
lobes
cycles
ionospheres
magnetosphere
magnetospheres
modeling
topology
cells
convection
reciprocation

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)
  • Palaeontology

Cite this

A Magnetohydrodynamic Modeling of the Interchange Cycle for Oblique Northward Interplanetary Magnetic Field. / Watanabe, Masakazu; Fujita, Shigeru; Tanaka, Takashi; Kubota, Yasubumi; Shinagawa, Hiroyuki; Murata, Ken T.

In: Journal of Geophysical Research: Space Physics, Vol. 123, No. 1, 01.01.2018, p. 272-286.

Research output: Contribution to journalArticle

Watanabe, Masakazu ; Fujita, Shigeru ; Tanaka, Takashi ; Kubota, Yasubumi ; Shinagawa, Hiroyuki ; Murata, Ken T. / A Magnetohydrodynamic Modeling of the Interchange Cycle for Oblique Northward Interplanetary Magnetic Field. In: Journal of Geophysical Research: Space Physics. 2018 ; Vol. 123, No. 1. pp. 272-286.
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