Implications of solar wind suprathermal tails for IBEX ENA images of the heliosheath

C. Prested, N. Schwadron, J. Passuite, B. Randol, B. Stuart, G. Crew, J. Heerikhuisen, N. Pogorelov, G. Zank, M. Opher, F. Allegrini, D. J. McComas, M. Reno, E. Roelof, S. Fuselier, H. Funsten, E. Moebius, L. Saul

Research output: Contribution to journalArticlepeer-review

50 Scopus citations

Abstract

Decades of interplanetary measurements of the solar wind and other space plasmas have established that the suprathermal ion intensity distributions (j) are non-Maxwellian and are characterized by high-energy power law tails (j ∼ E-k). Recent analysis by Fisk and Gloeckler of suprathermal ion observations between 1-5 AU demonstrates that a particular differential intensity distribution function emerges universally between ∼2-10 times the solar wind speed with κ ∼ 1.5. This power law tail is particularly apparent in downstream distributions beyond reverse shocks associated with corotating interaction regions. Similar power law tails have been observed in the downstream flow beyond the termination shock by the Low Energy Charged Particle instrument on both Voyager 1 and Voyager 2. Using kappa distributions with internal energy, density, and bulk flow derived from large-scale magnetohydrodynamic models, we calculate the simulated flux of energetic neutral atoms (ENAs) produced in the heliosheath by charge exchange between solar wind protons and interstellar hydrogen. We then produce simulated ENA maps of the heliosheath, such as will be measured by the Interstellar Boundary Explorer Mission (IBEX). We also estimate the expected signal to noise and background ratio for IBEX. The solar wind suprathermal tail significantly increases the ENA flux within the IBEX energy range, ∼0.01-6 keV, by more than an order of magnitude at the highest energies over the estimates using a Maxwellian. It is therefore essential to consider suprathermal tails in the interpretation of IBEX ENA images and theoretical modeling of the heliospheric termination shock.

Original languageEnglish (US)
Article numberA06102
JournalJournal of Geophysical Research: Space Physics
Volume113
Issue number6
DOIs
StatePublished - Jun 1 2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Fingerprint Dive into the research topics of 'Implications of solar wind suprathermal tails for IBEX ENA images of the heliosheath'. Together they form a unique fingerprint.

Cite this