Magnetotail energy storage and the variability of the magnetotail current sheetThe antiparallel field configuration in the earth magnetotail is a prime location to search for the important astrophysical process known as magnetic reconnection. The magnetic evidence that reconnection occurs in the earth's magnetotail is that the energy of the tail invariably decreases at the time of global substorm onsets, and that an increased number of closed field lines are seen in the near-earth magnetotail after substorms. This increased northward flux is often convecting earthward from the expected site of the X line after the substorm onset, while southward flux is often convecting tailward. Prior to a substorm, energy accumulates in the tail as the field assumes a more taillike configuration with a smaller field component across the equatorial plane. The high-beta plasma sheet becomes thin and has been observed to be at least as thin as a few thousand km near substorm onset times. The small Bn component and thin plasma sheet are the conditions which favor the onset of the tearing-mode instability, which is thought to lead to neutral-line formation and the reconnection associated with substorm onset. Intervals of weak and highly variable fields in the plasma sheet provide evidence for the tearing-mode instability.
Document ID
19850061369
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Fairfield, D. H. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 12, 2013
Publication Date
January 1, 1984
Subject Category
Geophysics
Meeting Information
Meeting: Magnetic reconnection in space and laboratory plasmas