MHD modeling of magnetotail instability for localized resistivity

Journal Article · Sun May 01 04:00:00 EDT 1994 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/94JA00441· OSTI ID:255680

Hesse, M ^[1]; Birn, J ^[2]

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1. NASA Goddard Space Flight Center, Greenbelt, MD (United States)
2. Los Alamos National Lab., NM (United States)

The authors present results of a three-dimensional MHD simulation of magnetotail evolution initiated by a sudden occurrence or increase of spatially localized resistivity as the major expected consequence of some localized microinstability. Because of the absence of a quantitative model, possible variations of resistivity levels with current density, or the reduction thereof, are not incorporated in the present investigation. The emphasis of the study is on an investigation of the changes to the overall evolution brought about by this localization, in particular, on the disruption and diversion of the cross-tail current and the non-linear evolution of the magnetotail instability. The immediate consequences of the occurrence of the localized resistance and the resulting electric field are a reduction and diversion of the electric current around the region of high resistivity, associated with an increase of B{sub z} ({open_quotes}dipolarization{close_quotes}) at the earthward edge and a decrease of B{sub z} at the tailward edge of this region. These effects, however, are localized and do not involve a reduction of the total cross-tail current and hence do not lead to the global development of a {open_quotes}substorm current wedge,{close_quotes} which includes not only the reduction of the cross-tail current but also the buildup of a global field-aligned current system of {open_quotes}region 1{close_quotes} type (toward the Earth on the dawnside and away on the duskside of the tail). Such signatures develop at a later time, as consequences of a three-dimensional tearing instability, which is triggered by the occurrence of the resistivity. These features are found in combination with plasmoid formation and ejection, quite similar to results of earlier simulations with uniform resistivity.30 refs., 8 figs.

• OSTI ID: 255680
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: A5 Vol. 99; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
DISTURBANCES
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
MAGNETIC STORMS
MAGNETOTAIL
NONLINEAR PROBLEMS
PLASMA INSTABILITY
SIMULATION