Role of inductive electric fields and currents in dynamical ionospheric situations
We study the role of ionospheric induction in different commonly observed ionospheric situations. These include an intensifying electrojet, westward travelling surge (WTS) and Ω-band. We use data based, realistic models for these phenomena and calculate the inductive electric fields tha...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2007-03-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/25/437/2007/angeo-25-437-2007.pdf |
| _version_ | 1818502315004395520 |
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| author | H. Vanhamäki O. Amm A. Viljanen |
| author_facet | H. Vanhamäki O. Amm A. Viljanen |
| author_sort | H. Vanhamäki |
| collection | DOAJ |
| description | We study the role of ionospheric induction in different commonly observed
ionospheric situations. These include an intensifying electrojet, westward
travelling surge (WTS) and Ω-band. We use data based, realistic models
for these phenomena and calculate the inductive electric fields that are
created due to the temporal variations of ionospheric currents. The
ionospheric induction problem is solved using a new calculation technique
that can handle non-uniform, time-dependent conductances and electric fields
of any geometry. We find that in some situations inductive effects are not
negligible and the ionospheric electric field is not a pure potential field,
but has a significant induced rotational part. In the WTS and Ω-band
models the induced electric field is concentrated in a small area, where the
time derivatives are largest. In the electrojet model the induced field is
significant over a large part of the jet area. In these examples the induced
electric field has typical values of few mV/m, which amounts to
several tens of percents of the potential electric field present at the same
locations. The induced electric field is associated with ionospheric and
field aligned currents (FAC), that modify the overall structure of the
current systems. Especially the induced FAC are often comparable to the
non-inductive FAC, and may thus modify the coupling between the ionosphere
and magnetosphere in the most dynamical situations. We also present some
examples with very simple ionospheric current systems, where the effect of
different ionospheric parameters on the induction process is studied. |
| first_indexed | 2024-12-10T21:08:36Z |
| format | Article |
| id | doaj.art-e39b86ab1eb14edfa8bc6c4deffebfbe |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-10T21:08:36Z |
| publishDate | 2007-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-e39b86ab1eb14edfa8bc6c4deffebfbe2022-12-22T01:33:33ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762007-03-012543745510.5194/angeo-25-437-2007Role of inductive electric fields and currents in dynamical ionospheric situationsH. Vanhamäki0O. Amm1A. Viljanen2Finnish Meteorological Institute, Space Research Unit, P.O. Box 503, 00101 Helsinki, FinlandFinnish Meteorological Institute, Space Research Unit, P.O. Box 503, 00101 Helsinki, FinlandFinnish Meteorological Institute, Space Research Unit, P.O. Box 503, 00101 Helsinki, FinlandWe study the role of ionospheric induction in different commonly observed ionospheric situations. These include an intensifying electrojet, westward travelling surge (WTS) and Ω-band. We use data based, realistic models for these phenomena and calculate the inductive electric fields that are created due to the temporal variations of ionospheric currents. The ionospheric induction problem is solved using a new calculation technique that can handle non-uniform, time-dependent conductances and electric fields of any geometry. We find that in some situations inductive effects are not negligible and the ionospheric electric field is not a pure potential field, but has a significant induced rotational part. In the WTS and Ω-band models the induced electric field is concentrated in a small area, where the time derivatives are largest. In the electrojet model the induced field is significant over a large part of the jet area. In these examples the induced electric field has typical values of few mV/m, which amounts to several tens of percents of the potential electric field present at the same locations. The induced electric field is associated with ionospheric and field aligned currents (FAC), that modify the overall structure of the current systems. Especially the induced FAC are often comparable to the non-inductive FAC, and may thus modify the coupling between the ionosphere and magnetosphere in the most dynamical situations. We also present some examples with very simple ionospheric current systems, where the effect of different ionospheric parameters on the induction process is studied.https://www.ann-geophys.net/25/437/2007/angeo-25-437-2007.pdf |
| spellingShingle | H. Vanhamäki O. Amm A. Viljanen Role of inductive electric fields and currents in dynamical ionospheric situations Annales Geophysicae |
| title | Role of inductive electric fields and currents in dynamical ionospheric situations |
| title_full | Role of inductive electric fields and currents in dynamical ionospheric situations |
| title_fullStr | Role of inductive electric fields and currents in dynamical ionospheric situations |
| title_full_unstemmed | Role of inductive electric fields and currents in dynamical ionospheric situations |
| title_short | Role of inductive electric fields and currents in dynamical ionospheric situations |
| title_sort | role of inductive electric fields and currents in dynamical ionospheric situations |
| url | https://www.ann-geophys.net/25/437/2007/angeo-25-437-2007.pdf |
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