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| Titel |
Solar wind plasma interaction with solar probe plus spacecraft |
| VerfasserIn |
S. Guillemant, V. Génot, J.-C. Matéo-Vélez, R. Ergun, P. Louarn |
| 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 ; 30, no. 7 ; Nr. 30, no. 7 (2012-07-24), S.1075-1092 |
| Datensatznummer |
250017245
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| Publikation (Nr.) |
 copernicus.org/angeo-30-1075-2012.pdf |
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| Zusammenfassung |
| 3-D PIC (Particle In Cell) simulations of spacecraft-plasma interactions in
the solar wind context of the Solar Probe Plus mission are presented. The
SPIS software is used to simulate a simplified probe in the near-Sun
environment (at a distance of 0.044 AU or 9.5 RS from the Sun
surface). We begin this study with a cross comparison of SPIS with another
PIC code, aiming at providing the static potential structure surrounding a
spacecraft in a high photoelectron environment. This paper presents then a
sensitivity study using generic SPIS capabilities, investigating the role of
some physical phenomena and numerical models. It confirms that in the near-
sun environment, the Solar Probe Plus spacecraft would rather be negatively
charged, despite the high yield of photoemission. This negative potential is
explained through the dense sheath of photoelectrons and secondary electrons
both emitted with low energies (2–3 eV). Due to this low energy of
emission, these particles are not ejected at an infinite distance of the
spacecraft and would rather surround it. As involved densities of
photoelectrons can reach 106 cm−3 (compared to ambient ions and
electrons densities of about 7 × 103 cm−3), those
populations affect the surrounding plasma potential generating potential
barriers for low energy electrons, leading to high recollection. This
charging could interfere with the low energy (up to a few tens of eV) plasma
sensors and particle detectors, by biasing the particle distribution
functions measured by the instruments. Moreover, if the spacecraft charges to
large negative potentials, the problem will be more severe as low energy
electrons will not be seen at all. The importance of the modelling
requirements in terms of precise prediction of spacecraft potential is also
discussed. |
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