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| Titel |
Comment on Lockwood and Davis, "On the longitudinal extent of magnetopause reconnection pulses" |
| VerfasserIn |
W. J. Heikkila |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 17, no. 2 ; Nr. 17, no. 2, S.173-177 |
| Datensatznummer |
250013669
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| Publikation (Nr.) |
 copernicus.org/angeo-17-173-1999.pdf |
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| Zusammenfassung |
| Lockwood and Davis (1996) present a concise
description of magnetopause reconnection pulses, with the claimed support of
three types of observations: (1) flux transfer events (FTE), (2) poleward-moving
auroral forms on the dayside, and (3) steps in cusp ion dispersion
characteristics. However, there are a number of errors and misconceptions in the
paper that make their conclusions untenable. They do not properly take account
of the fact that the relevant processes operate in the presence of a plasma.
They fail to notice that the source of energy (a dynamo with E · J<0)
must be close to the region of dissipation (the electrical load with E ·
J>0) in transient phenomena, since energy (or information) cannot
travel faster than the group velocity of waves in the medium (here the Alfvén
velocity VA). In short, Lockwood and Davis use the wrong
contour in their attempt to evaluate the electromotive force (emf). This
criticism goes beyond their article: a dynamo is not included in the usual
definition of reconnection, only the reconnection load. Without an explicit
source of energy in the assumed model, the idea of magnetic reconnection is
improperly posed. Recent research has carried out a superposed epoch analysis of
conditions near the dayside magnetopause and has found the dynamo and the load,
both within the magnetopause current sheet. Since the magnetopause current is
from dawn to dusk, the sign of E · J reflects the sign of the
electric field. The electric field reverses, within the magnetopause; this can
be discovered by an application of Lenz's law using the concept of erosion of
the magnetopause. The net result is plasma transfer across the magnetopause to
feed the low latitude boundary layer, at least partly on closed field lines, and
viscous interaction as the mechanism by which solar wind plasma couples to the
magnetosphere. |
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