skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Helium Energetic Neutral Atoms from the Heliosphere: Perspectives for Future Observations

Abstract

Observations of energetic neutral atoms (ENAs) allow for remote sensing of plasma properties in distant regions of the heliosphere. So far, most of the observations have concerned only hydrogen atoms. In this paper, we present perspectives for observations of helium energetic neutral atoms (He ENAs). We calculated the expected intensities of He ENAs created by the neutralization of helium ions in the inner heliosheath and through the secondary ENA mechanism in the outer heliosheath. We found that the dominant source region for He ENAs is the inner heliosheath. The obtained magnitudes of intensity spectra suggest that He ENAs can be observed with future ENA detectors, as those planned on Interstellar Mapping and Acceleration Probe . Observing He ENAs is most likely for energies from a few to a few tens of keV/nuc. Estimates of the expected count rates show that the ratio of helium to hydrogen atoms registered in the detectors can be as low as 1:10{sup 4}. Consequently, the detectors need to be equipped with an appropriate mass spectrometer capability, allowing for recognition of chemical elements. Due to the long mean free paths of helium ions in the inner heliosheath, He ENAs are produced also in the distant heliosphericmore » tail. This implies that observations of He ENAs can resolve its structure, which seems challenging from observations of hydrogen ENAs since energetic protons are neutralized before they progress deeper in the heliospheric tail.« less

Authors:
; ;  [1]
  1. Space Research Centre of the Polish Academy of Sciences (CBK PAN), Bartycka 18A, 00-716 Warsaw (Poland)
Publication Date:
OSTI Identifier:
22663623
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 840; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ATOMS; CONCENTRATION RATIO; HELIOSPHERE; HELIUM; HELIUM IONS; HYDROGEN; KEV RANGE; MASS; MASS SPECTROMETERS; MEAN FREE PATH; PLASMA; PROTONS; SOLAR WIND; SPACE; SPACE VEHICLES; SPECTRA; SUN

Citation Formats

Swaczyna, Paweł, Grzedzielski, Stan, and Bzowski, Maciej, E-mail: pswaczyna@cbk.waw.pl. Helium Energetic Neutral Atoms from the Heliosphere: Perspectives for Future Observations. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA6D5B.
Swaczyna, Paweł, Grzedzielski, Stan, & Bzowski, Maciej, E-mail: pswaczyna@cbk.waw.pl. Helium Energetic Neutral Atoms from the Heliosphere: Perspectives for Future Observations. United States. doi:10.3847/1538-4357/AA6D5B.
Swaczyna, Paweł, Grzedzielski, Stan, and Bzowski, Maciej, E-mail: pswaczyna@cbk.waw.pl. Wed . "Helium Energetic Neutral Atoms from the Heliosphere: Perspectives for Future Observations". United States. doi:10.3847/1538-4357/AA6D5B.
@article{osti_22663623,
title = {Helium Energetic Neutral Atoms from the Heliosphere: Perspectives for Future Observations},
author = {Swaczyna, Paweł and Grzedzielski, Stan and Bzowski, Maciej, E-mail: pswaczyna@cbk.waw.pl},
abstractNote = {Observations of energetic neutral atoms (ENAs) allow for remote sensing of plasma properties in distant regions of the heliosphere. So far, most of the observations have concerned only hydrogen atoms. In this paper, we present perspectives for observations of helium energetic neutral atoms (He ENAs). We calculated the expected intensities of He ENAs created by the neutralization of helium ions in the inner heliosheath and through the secondary ENA mechanism in the outer heliosheath. We found that the dominant source region for He ENAs is the inner heliosheath. The obtained magnitudes of intensity spectra suggest that He ENAs can be observed with future ENA detectors, as those planned on Interstellar Mapping and Acceleration Probe . Observing He ENAs is most likely for energies from a few to a few tens of keV/nuc. Estimates of the expected count rates show that the ratio of helium to hydrogen atoms registered in the detectors can be as low as 1:10{sup 4}. Consequently, the detectors need to be equipped with an appropriate mass spectrometer capability, allowing for recognition of chemical elements. Due to the long mean free paths of helium ions in the inner heliosheath, He ENAs are produced also in the distant heliospheric tail. This implies that observations of He ENAs can resolve its structure, which seems challenging from observations of hydrogen ENAs since energetic protons are neutralized before they progress deeper in the heliospheric tail.},
doi = {10.3847/1538-4357/AA6D5B},
journal = {Astrophysical Journal},
number = 2,
volume = 840,
place = {United States},
year = {Wed May 10 00:00:00 EDT 2017},
month = {Wed May 10 00:00:00 EDT 2017}
}