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Is there an electrostatic field tangential to the dayside magnetopause and neutral line?
Author(s) -
Heikkila W. J.
Publication year - 1975
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl002i004p00154
Subject(s) - magnetopause , physics , electric field , equipotential , geophysics , magnetosphere , field line , dissipation , computational physics , magnetosheath , mechanics , magnetic field , quantum mechanics , thermodynamics
The question of possible energy dissipation that might be associated with the dayside magnetopause current requires consideration of the tangential component of the electric field. If the total current of 9 × 10 6 amperes flowed through the average magnetospheric dawn‐dusk potential difference of 6 × 10 4 volts the power dissipation would be 5 × 10 11 watts. We might expect this energy to be carried away by energized particles, perhaps as increased thermal or flow energy at or near the magnetopause boundary layer or mantle. Satellite observations are available, but they do not provide evidence of such energization. This failure leads us to conclude that the magnetopause current does not flow through the magnetospheric potential difference, and that the magnetopause is approximately an equipotential surface. Because of the necessary continuity of the tangential component of the electric field, this conclusion implies that there is no steady state electric field along the neutral or X‐line that must be located near the dayside magnetopause in an open magnetospheric model (which is clearly supported by other evidence). Such an electric field is an essential part of the theory of merging or reconnection of magnetic field lines, and it is therefore concluded that the merging model for the electric field is not correct. This conclusion could be avoided if some evidence for the implied energy dissipation were found.