Anomalous cosmic rays as a source of energetic neutral atoms in the heliosphere Original Research Article

Anomalous cosmic ray (ACR) ions in the distant heliosphere are potentially one of the important heliospheric sources of energetic neutral atoms (ENAs), which derive from the energetic ions neutralized by charge exchange with low energy atoms of the background interstellar gas. ENAs are unaffected by magnetic fields and move almost freely over large distances. This offers a possibility of imaging the original ion distribution in the distant heliosphere from the vicinity of the Earthʹs orbit, provided that the flux intensity of ENAs can be high enough to identify this contribution. In the following the theoretical models and the experimental data (detection of ENA by CELIAS/HSTOF on SOHO) are reviewed and discussed.