The solar wind as a possible source of fast temporal variations of the heliospheric ribbon [electronic resource].

Published:: Washington, D.C. : United States. Dept. of Energy. Office of Science, 2013.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
Physical Description:: Article numbers 109 : digital, PDF file
Additional Creators:: United States. Department of Energy. Office of Science and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

Here we present a possible source of pickup ions (PUIs) the ribbon observed by the Interstellar Boundary EXplorer (IBEX). We suggest that a gyrating solar wind and PUIs in the ramp and in the near downstream region of the termination shock (TS) could provide a significant source of energetic neutral atoms (ENAs) in the ribbon. A fraction of the solar wind and PUIs are reflected and energized during the first contact with the TS. Some of the solar wind may be reflected propagating toward the Sun but most of the solar wind ions form a gyrating beam-like distribution that persists until it is fully thermalized further downstream. Depending on the strength of the shock, these gyrating distributions can exist for many gyration periods until they are scattered/thermalized due to wave-particle interactions at the TS and downstream in the heliosheath. During this time, ENAs can be produced by charge exchange of interstellar neutral atoms with the gyrating ions. In order to determine the flux of energetic ions, we estimate the solar wind flux at the TS using pressure estimates inferred from in situ measurements. Assuming an average path length in the radial direction of the order of a few AU before the distribution of gyrating ions is thermalized, one can explain a significant fraction of the intensity of ENAs in the ribbon observed by IBEX. In conclusion, with a localized source and such a short integration path, this model would also allow fast time variations of the ENA flux.

Report Numbers:

E 1.99:1326049

Subject(s):

Astronomy And Astrophysics

Other Subject(s):

Note:

Published through SciTech Connect.
10/04/2013.
Astrophysical Journal 776 2 ISSN 0004-637X AM
H. Kucharek; S. A. Fuselier; P. Wurz; N. Pogorelov; S. Borovikov; M. A. Lee; E. Moebius; D. Reisenfeld; H. Funsten; N. Schwadron; D. McComas.
Univ. of Alabama in Huntsville, AL (United States)

Funding Information:

SC0008334
NNX09AG62G

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