Numerical simulations of primary and secondary hydrogen ENA fluxes at 1 AU

Abstract

The interaction between the solar wind (SW) and the local interstellar medium (LISM) creates energetic neutral atoms (ENAs), mainly Hydrogen (H), at energies similar to ions in the SW. H ENAs are born from charge exchanges between SW protons and LISM H atoms. A large portion of measurable primary ENAs are born in the inner heliosheath (IHS), where the heated and condensed SW plasma has a large thermal component to direct ENAs back toward 1 AU. Secondary ENAs, however, require secondary charge exchanges before being detected at 1 AU. Primary ENAs born in the supersonic and subsonic SW may exit the HP, charge exchange into pick-up ions (PUIs), and charge exchange again to become secondary ENAs. Recent IBEX observations show a ribbon of flux dominating the entire sky. It is possible that the IBEX ribbon is created through secondary charge exchange processes. In this paper we present a numerical code that calculates primary and secondary H ENA fluxes by integrating along ENA trajectories. We will provide descriptions of the code and preliminary results.