Pick-up ions in the outer heliosheath: A possible mechanism for the interstellar boundary explorer ribbon

J. Heerikhuisen, N. V. Pogorelov, G. P. Zank, G. B. Crew, P. C. Frisch, H. O. Funsten, P. H. Janzen, D. J. McComas, D. B. Reisenfeld, N. A. Schwadron

Research output: Contribution to journalArticlepeer-review

227 Scopus citations


First data from NASA's Interstellar Boundary EXplorer (IBEX) mission show a striking "ribbon" feature of enhanced energetic neutral atom (ENA) emission. The enhancement in flux is between 2 and 3 times greater than adjacent regions of the sky. Yet the spectral index of ENAs appears to be the same both inside and outside the ribbon. While the ribbon itself was not predicted by any models of the heliospheric interface, its geometry appears to be related to the predicted interstellar magnetic field (ISMF) outside the heliopause (HP). In this Letter, we examine a process of ENA emission from the outer heliosheath, based on a source population of non-isotropic pick-up ions that themselves originate as ENAs from inside the HP. We find that our simplistic approach yields a ribbon of enhanced ENA fluxes as viewed from the inner heliosphere with a spatial location and ENA flux similar to the IBEX measurements, with the provision that the ions retain a partial shell distribution long enough for the ions to be neutralized. As a corollary, our idealized simulation of this mechanism suggests that ISMF is likely oriented close to the center of the observed ribbon.

Original languageEnglish
Pages (from-to)L126-L130
JournalAstrophysical Journal Letters
Issue number2 PART 2
StatePublished - 2010


  • Kinematics and dynamics
  • Magnetic fields
  • Solar wind


Dive into the research topics of 'Pick-up ions in the outer heliosheath: A possible mechanism for the interstellar boundary explorer ribbon'. Together they form a unique fingerprint.

Cite this