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| Titel |
3D Global PIC simulation of Cusp Dynamics and Alfvenic transition layers at cusp outer boundary during IMF rotations from north to south |
| VerfasserIn |
DongSheng Cai, Bertrand Lembège, Amin Esmaeili, Ken-ichi Nishikawa |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096813
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| Publikation (Nr.) |
 EGU/EGU2014-12336.pdf |
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| Zusammenfassung |
| The first 3D global full electro-magnetic particle-in-cell (PIC) simulations in the global
view of solar-wind-magnetosphere interaction are performed,and compared with
the statistical surveys of the plasma flows measured by the CLUSTER satellites
in the high-altitude cusp region of the Northern Hemisphere. he magnetospheric
polar cusp regions are considered to be key regions to transfer mass, and energy
from the solar-wind to the plasma sheet. Using the global PIC simulation, we try to
understand these key regions and the dynamical interactions that occur there. Statistical
experimental observations of the cusp boundaries from CLUSTER mission made by
Lavraud et al. (2005) have clearly evidenced the presence of a transition layer inside
the magnetosheath near the outer boundary of the cusp. This layer characterized
by Log(MA) ~ 1 allows a transition from super-Alfvenic to sub-Alfvenic bulk
flow from the exterior to the interior side of the outer cusp and has been mainly
observed experimentally under northward interplanetary magnetic field (IMF). The role
of this layer is important in order to understand the flow variations (and later the
entry and precipitation of particles) when penetrating the outer boundary of the
cusp. In order to analyze this layer, a large 3D PIC simulation of the global solar
wind-terrestrial magnetosphere interaction have been performed, and the attention has been
focused on the cusp region and its nearby surrounding during IMF rotation from
north to south. Present results retrieve quite well the presence of this layer within
the meridian plane for exactly northward IMF, but its location differs in the sense
that it is located slightly below the X reconnection region associated to the nearby
magnetopause (above the outer boundary of the cusp). In order to clarify this question, an
extensive study has been performed as follows: (i) a 3D mapping of this transition
layer in order to analyze more precisely the thickness, the location and the spatial
extension of this layer on the magnetosphere flanks for a fixed Northward IMF
configuration; (ii) a parametric study in order to analyze the impact of the IMF rotation from
north to south on the persistence and the main features of this transition layer; (iii)
following these analysis, a 3D mapping and analysis of particle distributions from
this transition layer to the so-called stagnant cusp exterior in order to reveal the
mechanism of this layer. We show how these transition layers render the flow from
super to sub Alfvenic and allow the particles enter into the magnetic cusp region. |
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