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Titel |
A numerical study of the interaction between two ejecta in the interplanetary medium: one- and two-dimensional hydrodynamic simulations |
VerfasserIn |
A. Gonzalez-Esparza, A. Santillán, J. Ferrer |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
0992-7689
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Digitales Dokument |
URL |
Erschienen |
In: Annales Geophysicae ; 22, no. 10 ; Nr. 22, no. 10 (2004-11-03), S.3741-3749 |
Datensatznummer |
250015045
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Publikation (Nr.) |
copernicus.org/angeo-22-3741-2004.pdf |
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Zusammenfassung |
We studied the heliospheric evolution in one and two dimensions
of the interaction between two
ejecta-like disturbances beyond the critical point:
a faster ejecta 2 overtaking a previously
launched slower ejecta 1.
The study is based on a
hydrodynamic model using the ZEUS-3-D code.
This model can be applied to those cases where the interaction occurs
far away from the Sun and there is no merging
(magnetic reconnection) between the two ejecta.
The simulation shows that when the faster
ejecta 2 overtakes ejecta 1 there is
an interchange of momentum between the two ejecta, where the leading
ejecta 1 accelerates and the tracking ejecta 2 decelerates. Both ejecta tend
to arrive at 1AU having similar speeds, but with the front of ejecta 1
propagating faster than the front of ejecta 2.
The momentum is transferred from ejecta 2 to ejecta 1 when the shock
initially driven by ejecta 2 passes through ejecta 1.
Eventually the two shock waves driven by the two ejecta merge together into a
single stronger shock. The 2-D simulation shows that the evolution of
the interaction can be very complex and there are very different
signatures of the same event at different viewing angles; however, the
transferring of
momentum between the two ejecta follows the same physical mechanism
described above. These results are in qualitative agreement with
in-situ plasma observations of "multiple magnetic clouds" detected at 1AU. |
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