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| Titel |
How IMF Bx affects the two polar hemispheres differently |
| VerfasserIn |
Jone Peter Reistad, Nikolai Østgaard, Karl Magnus Laundal, Kjellmar Oksavik |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250072163
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| Zusammenfassung |
| From studying the aurora in both hemispheres simultaneously, mechanisms responsible for
producing asymmetric aurora have earlier been identified. One such mechanism believed to
be responsible for large-scale asymmetries on auroral brightness between the hemispheres is
the solar wind dynamo (E -
j < 0). In the presence of a significant Bx-component
in the interplanetary magnetic field during Bz negative, the solar wind dynamo
is suggested to be more prominent in one hemisphere compared to the other. By
utilizing the large IMAGE WIC database of global imaging of the aurora from the
Northern Hemisphere, we derive patterns of auroral intensities for a) when the
efficiency of this mechanism is believed to be important compared to other mechanisms,
and b) during similar conditions when the efficiency of the solar wind dynamo is
believed to be important in the opposite (southern) hemisphere. First results indicate a
distinct difference in intensity between the two cases. In order to investigate the
expected similar effect in the Southern Hemisphere, a similar analysis on the much
smaller dataset from the Polar VIS Earth camera will be conducted. In the Southern
Hemisphere we expect to see the same IMF Bx intensity dependence but for opposite
sign of IMF Bx. Also, MHD simulations of the magnetosphere system might be
utilized to further investigate any asymmetric flow speeds between the northern and
southern magnetosheaths expected from the suggested asymmetric dynamo action. |
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