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| Titel |
Pickup protons at quasi-perpendicular shocks: full particle electrodynamic simulations |
| VerfasserIn |
S. Matsukiyo, M. Scholer, D. Burgess |
| 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 ; 25, no. 1 ; Nr. 25, no. 1 (2007-02-01), S.283-291 |
| Datensatznummer |
250015777
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| Publikation (Nr.) |
 copernicus.org/angeo-25-283-2007.pdf |
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| Zusammenfassung |
| We have performed 3 one-dimensional full particle electromagnetic
simulations of a quasi-perpendicular shock with the same Alfvén
Mach number MA~5, shock normal-magnetic field angle
ΘBn=87° and ion and electron beta (particle to
magnetic field pressure) of 0.1. In the first run we used an ion to
electron mass ratio close to the physical one (mi/me=1024). As
expected from previous high mass ratio simulations the Modified
Two-Stream instability develops in the foot of the shock, and the
shock periodically reforms itself. We have then self-consistently
included in the simulation 10% pickup protons distributed on a
shell in velocity space as a third component. In a run with an
unrealistically low mass ratios of 200 the shock still reforms
itself; reformation is due to accumulation of specularly reflected
particles at the upstream edge of the foot. In a third run including
pickup protons we used a mass ratio of 1024. The shock reforms
periodically as in the low mass ratio run with a somewhat smaller
time constant. The specular reflection of pickup protons results in
an increase of the shock potential some distance ahead of the shock
foot and ramp. The minimum scale of the cross shock potential during
reformation is about 7 electron inertial length λe. We do
not find any pickup proton acceleration in the ramp or downstream of
the shock beyond the energy which specularly reflected ions gain by
the motional electric field of the solar wind during their upstream
gyration. |
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