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| Titel |
Current Closure from Polar to Equatorial Ionosphere via Cowling Channel |
| VerfasserIn |
Akimasa Yoshikawa, Aoi Nakamizo, Shin Ohtani |
| 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 |
250080553
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| Zusammenfassung |
| Possible mechanism for current closure from polar to equatorial ionosphere via global Cowling channel is discussed. In our model, a global (primary) Hall current accompanied by two-cell type ionospheric convection induces polarization chargee at the conductivity gradient region of dawn-dusk conductivity terminator and magnetic dip-equator. The secondary electric field accompanied by this induced charge generates the secondary Hall current flows along the dawn-side terminator line to the magnetic dip-equator. Resultantly, the global Cowling channel from polar to equatorial ionosphere via the terminator-line and magnetic-dip equator could be formed. Our model shows that growing of equatorial electrojet (EEJ) is due to the converging Hall current from polar region to the dawn side dip-equator and decaying of EEJ is due to the diverging Pedersen current from dusk-side dip-equator to the polar region. This mechanism can be applied to the EEJ disturbances accompanied by the solar wind variations such as DP2-type magnetic field disturbances and many phenomena associate the equatorial enhancement and/or depression of the geomagnetic field disturbances. |
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