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| Titel |
Field-Line Resonances in the Current Basis |
| VerfasserIn |
Katharina Ostaszewski, Karl-Heinz Glassmeier, Christian Nabert |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127390
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| Publikation (Nr.) |
 EGU/EGU2016-7261.pdf |
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| Zusammenfassung |
| The MHD theory of the field-line resonance is of great importance for the understanding of
ultra low-frequency waves in the magnetosphere. Most theoretical works concerning
field-line resonance use the electric field as the basis set. In an ideal MHD plasma the
field-aligned component of the electrical field vanishes because of the frozen-in theorem.
However, a field-aligned current flows to maintain quasi-neutrality. This field-aligned current
can only be carried by the transverse MHD Alfvèn wave and is therefore a characteristic
feature of these types of waves.
In this study we investigate the field-line resonance phenomenon using a three
dimensional current vector space as the basis set. Using the model of the box magnetosphere
of Southwood (1974) we derive an equation for the field-aligned current. This equation
provides a simpler and more detailed insight into the coupling process between the fast mode
and the Alfvèn mode.
Furthermore we investigate the effect of the Hall current on the field-aligned current by
including the Hall term in Ohm’s law. It is shown that in some situations the Hall
current can nullify the filed-aligned current and therefore prevent the resonance. |
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