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| Titel |
Latitude, Energy, and Time Variations of Energetic Neutral Atom Spectral indices Measured by IBEX |
| VerfasserIn |
Mihir Desai, David McComas, Maher Dayeh, Herbert Funsten, Nathan Schwadron, Jacob Heerikhuisen, Stephen Fuselier, Nikolai Pogorelov, Gary Zank, Frederic Allegrini |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250123027
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| Publikation (Nr.) |
 EGU/EGU2016-2196.pdf |
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| Zusammenfassung |
| We investigate the latitude, energy, and time variations of the globally distributed 0.5–6 keV
energetic neutral atom (ENA) spectra measured by the Interstellar Boundary Explorer
(IBEX) during the first 5 years of the mission. Our previous results based on the first
3 years of IBEX observations showed that the ENA spectral indices at the two
lowest energies (0.89 and 1.47 keV) exhibit no clear trend with ecliptic latitude
θ, while those at ∼2.29 and ∼3.41 keV exhibit a clear latitudinal pattern; flatter
spectra occur above 60˚ latitude and steeper spectra occur ±30˚ of the equator.
While these results confirmed the previously reported latitudinal organization of the
ENA spectra and their remarkable similarity to that of the solar wind (SW) speed
observed by Ulysses in the inner heliosphere, we also showed that, unlike previous
reports, the ∼0.5-6 keV globally distributed ENA spectral indices could not be
represented as single power laws over much of the sky, and that they depend on energy
and latitude. In this work we extend the above results to include years 4 and 5 of
IBEX observations and investigate if the spectral indices vary as a function of time.
Finally, we discuss implications of our results on models and simulations that seek to
map the IBEX ENA observations back to the latitudinal profile of the SW speed
structure observed in the inner heliosphere. We also discuss the implications of
these new results for observational requirements for upcoming missions like IMAP. |
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