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| Titel |
A Statistical Model of the Magnetotail Neutral Sheet |
| VerfasserIn |
Sudong Xiao, Tielong Zhang, Wolfgang Baumjohann, Rumi Nakamura, Yasong Ge, Aimin Du, Guoqiang Wang, Quanming Lu |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250101149
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| Publikation (Nr.) |
 EGU/EGU2015-242.pdf |
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| Zusammenfassung |
| The neutral sheet of the magnetotail is characterized by weak magnetic field, strong cross tail
current, and a reversal of the magnetic field direction across it. The dynamics of the earth’s
magnetosphere is greatly influenced by physical processes that occur near the neutral sheet.
However, the exact position of the neutral sheet is variable in time. It is therefore essential
to have a reliable estimate of the average position of the neutral sheet. Magnetic
field data from ten years of Cluster, nineteen years of Geotail, four years of TC
1, and seven years of THEMIS observations have been incorporated to obtain a
model of the magnetotail neutral sheet. All data in aberrated GSM (Geocentric Solar
Magnetospheric) coordinate system are normalized to the same solar wind pressure
condition. The shape and position of the neutral sheet, illustrated directly by the
separator of positive and negative Bx on the YZ cross sections, are fitted with a
displaced ellipse model. It is consistent with previous studies that the neutral sheet
becomes curvier in the YZ cross section when the dipole tilt increases, yet our
model shows the curviest neutral sheet compared with previous models. The new
model reveals a hinging distance very close to 10 RE at a reference solar wind
dynamic pressure of 2 nPa. We find that the earth dipole tilt angle not only affects
the neutral sheet configuration in the YZ cross section but also in the XZ cross
section. The neutral sheet becomes more tilting in the XZ cross section when the
dipole tilt increases. The effect of an interplanetary magnetic field (IMF) penetration
is studied, and an IMF By-related twisting of about 3°is found. Anticlockwise
twisting of the neutral sheet is observed, looking along the downtail direction, for a
positive IMF By, and clockwise twisting of the neutral sheet for a negative IMF By. |
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