Energetic particles from the outer heliosphere appearing as a secondary pick-up ion component

Abstract

In measured pick-up ion spectra a special spectral feature has been identified on the high side of the pick-up ion injection energy which cannot be explained as due to energy diffusion of primary pick-up protons originating from ionized interstellar H-atoms. As we can show, however, in the following article, this feature can be explained as a secondary pick-up ion feature due to ions originating from the charge exchange ionization of energetic neutral H-atoms entering the inner heliosphere and coming from their birth places in the heliosheath. It may thus be the case that energetic neutral H-atoms from the heliosheath region, searched for by experimenters for quite some time now, have already been seen as secondary pick-up ions in special features of measured distribution functions.