EFFECTS OF FAST AND SLOW SOLAR WIND ON THE ENERGETIC NEUTRAL ATOM (ENA) SPECTRA MEASURED BY THE INTERSTELLAR BOUNDARY EXPLORER (IBEX) AT THE HELIOSPHERIC POLES
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Dayeh-2012-Effects of fast and.pdf
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Author(s)
Dayeh, M. A.
McComas, David J.
Allegrini, F.
DeMajistre, R.
Desai, M. I.
Funsten, H. O.
Janzen, Paul H.
Livadiotis, G.
Randol, B. M.
Reisenfeld, D. B.
Date Issued
March 2012
Journal
Astrophysical Journal
Publisher
IOP Publishing
Citation
Dayeh, M. A., D. J. McComas, F. Allegrini, B. De Majistre, M. I. Desai, H. O. Funsten, P. Janzen, et al. “ EFFECTS OF FAST AND SLOW SOLAR WIND ON THE ENERGETIC NEUTRAL ATOM (ENA) SPECTRA MEASURED BY THE INTERSTELLAR BOUNDARY EXPLORER ( IBEX ) AT THE HELIOSPHERIC POLES .” The Astrophysical Journal 749, no. 1 (March 21, 2012): 50. © 2012 The American Astronomical Society
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Final published version
Abstract
We study the energy dependence of ~0.5-6 keV energetic neutral atom (ENA) spectra in the southern heliospheric polar region obtained during five six-month sky maps measured by IBEX-Hi. We calculate the spectral slopes in the south pole in four different energy bands, namely, ~0.7-1.1 keV, ~1.1-1.7 keV, ~1.7-2.7 keV, and ~2.7-4.3 keV. We show (1) a persistent flattening of the ENA spectrum between ~1 and 2 keV, (2) significantly different modes (2.31, 1.58, 0.97, and 1.44) for the distributions of the slopes in the four different energy bands, and (3) a general decrease with increasing energy in the widths (FWHM) and mode fluctuations (their spread) of the slope distributions. We also compare the averaged ENA spectra measured at the south pole and at mid-latitudes. We conclude that the flattening between ~1 and 2 keV in the polar spectrum (spectral break) is produced by an enhancement of ENAs created by charge exchange between interstellar neutrals and pick-up ions in the fast solar wind.
MIT Department
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.1088/0004-637x/749/1/50
