Asymmetric time-dependent and stationary magnetic reconnection at the dayside magnetopause

Journal Article · Wed Nov 01 04:00:00 EST 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA11p15099· OSTI ID:7188561

Scholer, M ^[1]

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1. Institut fuer extraterrestrische Physik, Max-Planck-Institut fuer Physik und Astrophysik Garching, Federal Republic of Germany (DE)

Using a two-dimensional compressible MHD code we have numerically studied the reconnection process at an interface where (1) the magnetic field is higher on one side than on the other and total pressure is in balance by a higher density on the weak field side, and where (2) the magnetic field is identical on both sides, but the temperature is higher on one side than on the other. Reconnection is caused by applying a localized resistivity in the center of the current sheet. The plasma is allowed to enter and exit freely at the boundaries. By using a system size with a large extension parallel to the current sheets, we are able to study time-dependent as well as steady state effects. Denoting the weak magnetic field or low temperature region as magnetosheath and the high magnetic field or high temperature region as magnetosphere we find the following. Sudden onset of reconnection causes the development of a bulge in the current layer. The bulge moves with about 70% of the magnetosheath Alfven speed along the magnetopause away from the reconnection region. The growth of the bulge normal to the magnetopause is proportional to the reconnection rate. For a ratio of magnetospheric to magnetosheath magnetic field larger than about 1.5 the bulge is almost exclusively on the magnetosheath side of the magnetopause current layer. The motion of the bulge along the magnetopause leads to signatures in the normal magnetic field component similar to the ones observed in flux transfer events. When the bulge has moved far enough from the reconnection site, stationary reconnection proceeds at the X line. If there exists initially a magnetic field difference across the magnetopause current layer, a slow mode shock is formed in the magnetosphere and possibly a strong intermediate shock is formed in the magnetosheath.

• OSTI ID: 7188561
• Journal Information: Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 94:A11; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASYMMETRY
BOUNDARY LAYERS
FLUID MECHANICS
HYDRODYNAMICS
LAYERS
MAGNETIC RECONNECTION
MAGNETOHYDRODYNAMICS
MAGNETOPAUSE
MECHANICS
SOLAR ACTIVITY
SOLAR WIND
TIME DEPENDENCE
TWO-DIMENSIONAL CALCULATIONS