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Title: Energetic neutral atoms measured by the interstellar boundary explorer (IBEX): Evidence for multiple heliosheath populations

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. In this paper, we extend the work of Desai et al. and Fuselier et al. and combine and compare ENA spectra from the first 3 yr of observations by the IBEX-Hi and -Lo ENA imagers along the lines-of-sight (LOSs) from the inner heliosphere through to the locations of Voyager 1 and 2 with results from an updated physics-based model of the three-dimensional heliosphere and its constituent ion populations. Our results show that (1) IBEX ENA fluxes and spectra above ∼0.7 keV measured along the LOSs of the Voyagers are consistent with several models in which the parent pickup ion (PUI) populations originate in the inner heliosheath, and (2) a significant fraction of lower energy ENAs between ∼0.1-0.5 keV may originate from interstellar neutral gas charge-exchanging with a non-thermalized (hot) population of PUIs in the outer heliosheath beyond the heliopause. We discuss the implications of ENAs observed by IBEX originating from distinct parent populations as well as from two distinct locations in the heliospheric interface. These results indicate that ENA spectralmore » measurements at various energies can be used to remotely probe distinct physical processes operating in vastly different regions of the distant heliosphere.« less
Authors:
; ; ; ;  [1] ; ; ;  [2] ;  [3] ; ; ; ;  [4] ;  [5]
  1. Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 (United States)
  2. Space Research Centre, PAS, Warsaw (Poland)
  3. Los Alamos National Laboratory, Los Alamos, New Mexico, NM 87545 (United States)
  4. The Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL 35805 (United States)
  5. Department of Physics and Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)
Publication Date:
OSTI Identifier:
22348313
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 780; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ATOMS; CHARGE EXCHANGE; COMPARATIVE EVALUATIONS; HELIOSPHERE; IMAGES; INTERFACES; INTERSTELLAR SPACE; IONS; KEV RANGE; LOSSES; SHOCK WAVES; SOLAR WIND; SPECTRA; SUN; VOYAGER SPACE PROBES