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| Titel |
On the electron temperature downstream of the solar wind termination shock |
| VerfasserIn |
I. V. Chashei, H. J. Fahr  |
| 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 ; 31, no. 7 ; Nr. 31, no. 7 (2013-07-09), S.1205-1212 |
| Datensatznummer |
250019064
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| Publikation (Nr.) |
 copernicus.org/angeo-31-1205-2013.pdf |
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| Zusammenfassung |
| In this paper we study the temperatures of electrons convected with the
solar wind to large solar distances and finally transported over the solar
wind termination shock. Nearly nothing, unless at high energies in the
cosmic ray regime, is known about the thermodynamical behaviour of these
distant electrons from in~situ plasma observations. Hence it is tacitly
assumed these electrons, due to their adiabatic behaviour and vanishing heat
conduction or energization processes, have rapidly cooled off to very low
temperatures once they eventually arrive at the solar wind termination
shock (at about 100 AU). In this paper we show that such electrons, however,
at their passage over the termination shock due to the shock–electric field
action undergo an over-adiabatic heating and therefore appear on the
downstream side as a substantially heated plasma species. Looking
quantitatively into this heating process we find that solar wind electrons
achieve temperatures of the order of 2–4 × 106 K downstream of the
termination shock, depending on the upstream solar wind bulk velocity and
the shock compression ratio. Hence these electrons therewith play an
important dynamical role in structuring this shock and determining the
downstream plasma flow properties. Furthermore, they present an additional
ionization source for incoming neutral interstellar hydrogen and excite
X-ray emission. They also behave similar to cosmic ray electrons and extend
to some limited region upstream of the shock of the order of 0.1 AU by
spatial diffusion and thereby also modify the upstream solar wind
properties. |
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