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| Titel |
Large amplitude solitary waves in and near the Earth’s magnetosphere, magnetopause and bow shock: Polar and Cluster observations |
| VerfasserIn |
C. Cattell, C. Neiman, J. Dombeck, J. Crumley, J. Wygant, C. A. Kletzing, W. K. Peterson, F. S. Mozer, M. André |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 10, no. 1/2 ; Nr. 10, no. 1/2, S.13-26 |
| Datensatznummer |
250007816
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| Publikation (Nr.) |
 copernicus.org/npg-10-13-2003.pdf |
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| Zusammenfassung |
| Solitary waves with
large electric fields (up to 100's of mV/m) have been observed
throughout the magnetosphere and in the bow shock. We discuss observations
by Polar at high altitudes ( ~ 4-8 RE ), during crossings of the plasma
sheet boundary and cusp, and new measurements by Polar at the equatorial
magnetopause and by Cluster near the bow shock, in the cusp and at the
plasma sheet boundary. We describe the results of a statistical study of
electron solitary waves observed by Polar at high altitudes. The mean
solitary wave duration was ~ 2 ms. The waves have velocities from ~ 1000
km/s to > 2500 km/s. Observed scale sizes (parallel to the
magnetic field) are on the order of 1-10lD,
with eF/kTe from ~ 0.01 to
O(1). The average speed of solitary waves at the plasma sheet boundary is
faster than the average speed observed in the cusp and at cusp injections.
The amplitude increases with both velocity and scale size. These
observations are all consistent with the identification of the solitary
waves as electron hole modes. We also report the discovery of solitary
waves at the magnetopause, observed in Polar data obtained at the subsolar
equatorial magnetopause. Both positive and negative potential structures
have been observed with amplitudes up to ~ 25 mV/m. The velocities range
from 150 km/s to >2500 km/s, with scale sizes the order of a kilometer
(comparable to the Debye length). Initial observations of solitary waves
by the four Cluster satellites are utilized to discuss the scale sizes and
time variability of the regions where the solitary waves occur.
Preliminary results from the four Cluster satellites have given a glimpse
of the spatial and temporal variability of the occurrence of solitary
waves and their association with other wave modes. In all the events
studied, significant differences were observed in the waveforms observed
simultaneously at the four locations separated by ~ 1000 km. When solitary
waves were seen at one satellite, they were usually also seen at the other
satellites within an interval of a few seconds. In association with an
energetic electron injection and a highly compressed magnetosphere,
Cluster has observed the largest amplitude solitary waves (>750 mV/m)
ever reported in the outer magnetosphere. |
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