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| Titel |
Spectral Properties of Energetic Neutral Atoms Measured by the Interstellar Boundary Explorer (IBEX) Along the Lines-of-Sight of Voyager |
| VerfasserIn |
Mihir Desai, David McComas, Stephen Fuselier, Maher Dayeh, Herbert Funsten, Jacob Heerikhuisen, Eric Zirnstein, Nikolai Pogorelov, Gary Zank |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250074688
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| Zusammenfassung |
| Energetic Neutral Atoms (ENAs) observed by the Interstellar Boundary Explorer (IBEX)
provide powerful diagnostics about the origin of the progenitor ion populations and the
physical mechanisms responsible for their production. Here we survey the fluxes, energy
spectra, and energy-dependence of the spectral indices of ~0.03-6 keV ENAs measured by
IBEX-Hi and IBEX-Lo along the lines-of-sight of Voyager 1 and 2. We compare the ENA
spectra observed at IBEX with predictions of models that simulate the microphysics of the
heliospheric termination shock to predict the shape and relative contributions of a variety
of heliosheath ion populations. We show: (1) The ENA spectra between ~0.7-6
keV do not exhibit sharp cut-offs at ~twice the solar wind speed as is typically
observed for shell-like PUI distributions in the heliosphere and are reasonably well
accounted for by most of the models. (2) The 0.03-0.7 keV ENA intensities are larger by
more than an order of magnitude compared with most existing models that do not
include contributions from ENAs generated in the outer heliosheath. We conclude
that the 0.7-5 keV ENAs at IBEX are generated by inner heliosheath PUIs in the
~0.5-5 keV energy range that are transmitted through the termination shock; the
PUI population being a superposition of Maxwellian or kappa distributions and
partially filled shell distributions in velocity space. In contrast, the parent PUI proton
population for the |
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