The Electromagnetic Field for an Open Magnetosphere

  1. Edward W. Hones Jr.
  1. Walter J. Heikkila

Published Online: 19 MAR 2013

DOI: 10.1029/GM030p0039

Magnetic Reconnection in Space and Laboratory Plasmas

Magnetic Reconnection in Space and Laboratory Plasmas

How to Cite

Heikkila, W. J. (1984) The Electromagnetic Field for an Open Magnetosphere, in Magnetic Reconnection in Space and Laboratory Plasmas (ed E. W. Hones), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM030p0039

Author Information

  1. Center for Space Sciences, the University of Texas at Dallas, Richardson, Texas 75080

Publication History

  1. Published Online: 19 MAR 2013
  2. Published Print: 1 JAN 1984

ISBN Information

Print ISBN: 9780875900582

Online ISBN: 9781118664223



  • Electric field;
  • Electromagnetic field;
  • Interplanetary magnetic field (IMF).;
  • Magnetopause;
  • Open magnetosphere


Two-dimensional steady-state theories of reconnection are based on an electric field that is constant across the separator line; consequently, curl E is assumed to vanish. However, a finite curl is required so that stored magnetic energy can be tapped, since ∂(B2/2μo)/∂t = H·∂B/∂t, and ∂B/∂t = − curl E. With reversal of the electric field at the magnetopause (which implies a finite curl), magnetosheath plasma can feed the boundary layers, just inside the magnetopause. Since the boundary layer plasma cannot all flow into the plasma sheet, it must continue flowing tailward, still on closed field lines. The topology of the assumed electric field must be revised from being everywhere in the dawn-dusk direction (in the reconnection model) to the reverse direction within the boundary layers. Even though the mechanism for creating this electric field may be transient, the polarization charge in the boundary layer is not lost immediately, and the electric field will be quasi-steady state, especially toward the flanks where there is always antisunward flow. This revision to the electric field profile implies that steady state reconnection may not be important in powering magnetospheric phenomena such as large scale circulation; localized and transient processes are more important, including impulsive transport of magnetosheath plasma to the boundary layers; and that the boundary layers provide the plasma, momentum, and energy to the plasma sheet, in a new kind of viscous interaction.