Influence of non-stationary electromagnetic field conditions on ion pick-up at Titan: 3-D multispecies hybrid simulations
Titan's interaction with the corotating Saturnian magnetospheric plasma is studied in terms of a three-dimensional electromagnetic hybrid model. This approach treats the electrons as a massless, charge-neutralizing fluid, whereas the ions are represented by macroparticles. The model consid...
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doaj-f6bf5deabcc54f498e72778efebe76422020-11-24T23:08:14ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762008-03-012659961710.5194/angeo-26-599-2008Influence of non-stationary electromagnetic field conditions on ion pick-up at Titan: 3-D multispecies hybrid simulationsS. Simon0U. Motschmann1U. Motschmann2K.-H. Glassmeier3Institute for Theoretical Physics, TU Braunschweig, GermanyInstitute for Theoretical Physics, TU Braunschweig, GermanyInstitute for Planetary Research, DLR, Berlin, GermanyInstitute for Geophysics and Extraterrestrial Physics, TU Braunschweig, GermanyTitan's interaction with the corotating Saturnian magnetospheric plasma is studied in terms of a three-dimensional electromagnetic hybrid model. This approach treats the electrons as a massless, charge-neutralizing fluid, whereas the ions are represented by macroparticles. The model considers two magnetospheric and three ionospheric ion species. In contrast to any foregoing simulation study, the magnetospheric upstream conditions are not assumed to be stationary, but time variations have been imposed on the electromagnetic fields. The model includes simple periodic distortions of the fields near Titan, the purpose being to illustrate the basic physical mechanisms of ion pick-up in a non-stationary electromagnetic environment. In order to allow a straightforward access to the influence of the electromagnetic field orientation on the pick-up, no variations have been imposed on the density of the impinging magnetospheric plasma. Under stationary upstream conditions, Titan's exospheric tail exhibits a strong asymmetry with respect to the direction of the convective electric field. The simulations show that this characteristic asymmetry cannot develop, if the ambient electromagnetic fields are highly distorted. However, the central tail region directly behind the satellite remains nearly unaffected by the distorted magnetospheric upstream conditions. The central tail where the slow ionospheric species are predominant is able to shield itself against any kind of distortion in the ambient magnetospheric field conditions. The shorter the time period of the distortions, the more efficient is this shielding effect. The dependency of the pick-up on the characteristic time scales of the distortions is discussed in detail for the investigated model cases. Besides, the reaction of Titan's exospheric tail structure on sudden, non-continuous changes of the magnetospheric plasma conditions is analyzed, providing an illustration of some effects that may occur when Titan crosses Saturn's magnetopause.https://www.ann-geophys.net/26/599/2008/angeo-26-599-2008.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
S. Simon U. Motschmann U. Motschmann K.-H. Glassmeier |
spellingShingle |
S. Simon U. Motschmann U. Motschmann K.-H. Glassmeier Influence of non-stationary electromagnetic field conditions on ion pick-up at Titan: 3-D multispecies hybrid simulations Annales Geophysicae |
author_facet |
S. Simon U. Motschmann U. Motschmann K.-H. Glassmeier |
author_sort |
S. Simon |
title |
Influence of non-stationary electromagnetic field conditions on ion pick-up at Titan: 3-D multispecies hybrid simulations |
title_short |
Influence of non-stationary electromagnetic field conditions on ion pick-up at Titan: 3-D multispecies hybrid simulations |
title_full |
Influence of non-stationary electromagnetic field conditions on ion pick-up at Titan: 3-D multispecies hybrid simulations |
title_fullStr |
Influence of non-stationary electromagnetic field conditions on ion pick-up at Titan: 3-D multispecies hybrid simulations |
title_full_unstemmed |
Influence of non-stationary electromagnetic field conditions on ion pick-up at Titan: 3-D multispecies hybrid simulations |
title_sort |
influence of non-stationary electromagnetic field conditions on ion pick-up at titan: 3-d multispecies hybrid simulations |
publisher |
Copernicus Publications |
series |
Annales Geophysicae |
issn |
0992-7689 1432-0576 |
publishDate |
2008-03-01 |
description |
Titan's interaction with the corotating Saturnian magnetospheric plasma is
studied in terms of a three-dimensional electromagnetic hybrid
model. This approach treats the electrons as a massless, charge-neutralizing
fluid, whereas the ions are represented by macroparticles.
The model considers two magnetospheric and three ionospheric ion species.
In contrast to any
foregoing simulation study, the magnetospheric upstream conditions are not assumed to be
stationary, but time variations have been imposed on the
electromagnetic fields.
The model includes simple periodic distortions of the
fields near
Titan, the purpose being to illustrate the basic physical mechanisms of ion
pick-up in a non-stationary electromagnetic environment.
In order to allow a straightforward access to the influence of the
electromagnetic field orientation on the pick-up, no variations
have been imposed on the density of the impinging magnetospheric plasma.
Under stationary upstream conditions, Titan's
exospheric tail exhibits a strong asymmetry with respect to the direction of
the convective electric field. The simulations show that this
characteristic asymmetry cannot develop,
if the ambient electromagnetic fields are highly distorted.
However, the central tail region directly behind the
satellite remains nearly unaffected by the distorted magnetospheric upstream
conditions.
The
central tail where the slow ionospheric species are predominant is able to shield
itself against any kind of distortion in the ambient magnetospheric field
conditions. The shorter the time period of the distortions, the more
efficient is this shielding effect. The dependency of the pick-up
on the characteristic time scales of the distortions is
discussed in detail for the
investigated model cases. Besides, the reaction of Titan's exospheric
tail structure on sudden, non-continuous changes of the magnetospheric plasma conditions
is analyzed, providing an illustration of some effects that may occur when Titan crosses Saturn's magnetopause. |
url |
https://www.ann-geophys.net/26/599/2008/angeo-26-599-2008.pdf |
work_keys_str_mv |
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