Structure of the dissipation region during magnetic reconnection in collisionless plasma

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA00893· OSTI ID:5222580

Burkhart, G R; Chen, J ^[1]; Drake, J F ^[2]

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1. Naval Research Lab., Washington, DC (USA)
2. Univ. of Maryland, College Park (USA)

The results of an analytic and numerical investigation of the structure of the X line during steady state magnetic reconnection in collisionless plasma are presented. The structure of the X line essentially depends on a single dimensionless parameter F, which is a measure of the influx of plasma into the reconnection region. For small F the self-consistent plasma current driven at the X line is small, and the magnetic fields are nearly unchanged from the initial vacuum state. With increasing F the current driven at the X line becomes large, and the dissipation region collapses in the direction of the inflow and elongates along the outflow. For sufficiently large F the velocity of the plasma ejected from the X line exceeds the local Alfven velocity. In this regime a fast mode shock forms at the outflow end of the dissipation region which slows the high-velocity outflow plasma to the subsonic flow characteristics of the broader outflow region. Finally, at a critical plasma flux F{sub c} the dissipation region collapses to zero thickness; no steady solutions are found for F > F{sub c}. By matching the energy dissipated at the neutral line with the change in global magnetic energy, a self-consistent equation for F is derived which indicates that F always adjusts so that F {approx lt} F{sub c}. Predictions of reconnection rates and associated parameters for the geomagnetic tail are presented which are in reasonable agreement with observations.

• OSTI ID: 5222580
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Journal Issue: A7 Vol. 96:A7; 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
ANALYTICAL SOLUTION
COLLISIONLESS PLASMA
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ENERGY LOSSES
FLUID FLOW
FLUID MECHANICS
HYDRODYNAMICS
INTERACTIONS
LOSSES
MAGNETIC RECONNECTION
MAGNETOHYDRODYNAMICS
MAGNETOTAIL
MECHANICS
NUMERICAL SOLUTION
PLASMA
SHOCK WAVES
SOLAR ACTIVITY
SOLAR WIND
SUBSONIC FLOW