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Titel |
2D PIC simulations of a curved supercritical shock: dynamics of the whistler precursor |
VerfasserIn |
Joël Stienlet, Philippe Savoini, Bertrand Lembège |
Konferenz |
EGU General Assembly 2010
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 12 (2010) |
Datensatznummer |
250041495
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Zusammenfassung |
The whistler precursor emitted from the curved terrestrial shock front plays an important role
in pre-decelerating and heating the incoming solar wind. Most previous works have mainly
analyzed the features of the whistler precursor emission for a 1D planar shock where it is
forced to propagate along the shock normal (Liewer and al, 1991) or to propagate obliquely
with respect to a fixed shock normal direction in 2D planar shock simulation (Krauss-Varban
et al., 1995). In the present case, the dynamics of the precursor is analyzed with
the help of a 2D full particle simulation for a continuously curved shock within
the angular range 90o -¥ θBn -¥ 45o where θBn is the angle between the shock
normal and the upstream magnetostatic field. Both electrons and ions dynamics are
described by a self consistent approach. Our results show that (i) the whistler precursor
extends far from the shock front mainly along the magnetostatic field (projected
on the simulation plane) and not along the shock normal; (ii) the width of these
curved wave fronts (precursor) strongly decreases when moving far from the shock
front; (iii) at the shock front, the precursor is emitted within an angular range much
larger than that predicted by linear theory; (iv) the damping rate of the whistler
precursor is analyzed for different directions of the shock normal. Wave particle
energy transfer is analysed, and these results will be discussed and compared with
previous 1D and 2D simulations of planar shocks; (v) the whistler precursor is not
monochromatic, and interferences between modes are evidenced by beats and wave-packets
in front of the shock. The impact of this effect on damping rate measurements will be
discussed. |
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