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| Titel |
Collisionless electrons in a thin high Mach number shock: dependence on angle and b |
| VerfasserIn |
M. Gedalin, E. Griv |
| 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 ; 17, no. 10 ; Nr. 17, no. 10, S.1251-1259 |
| Datensatznummer |
250013819
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| Publikation (Nr.) |
 copernicus.org/angeo-17-1251-1999.pdf |
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| Zusammenfassung |
It is widely believed that electron dynamics
in the shock front is essentially collisionless and determined by the
quasistationary magnetic and electric fields in the shock. In thick shocks the
electron motion is adiabatic: the magnetic moment is conserved throughout the
shock and v2^ ∝ B.
In very thin shocks with large cross-shock potential (the last feature is
typical for shocks with strong electron heating), electrons may become
demagnetized (the magnetic moment is no longer conserved) and their motion may
become nonadiabatic. We consider the case of substantial demagnetization in the
shock profile with the small-scale internal structure. The dependence of
electron dynamics and downstream distributions on the angle between the shock
normal and upstream magnetic field and on the upstream electron temperature is
analyzed. We show that demagnetization becomes significantly stronger with the
increase of obliquity (decrease of the angle) which is related to the more
substantial influence of the inhomogeneous parallel electric field. We also show
that the demagnetization is stronger for lower upstream electron temperatures
and becomes less noticeable for higher temperatures, in agreement with
observations. We also show that demagnetization results, in general, in
non-gyrotropic down-stream distributions.
Key words. Interplanetary physics (interplanetary
shocks; planetary bow shocks) |
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