Authors: Parisa Mostafavi (Johns Hopkins University Applied Physics Lab), Gary Zank, Matt Hill, Merav Opher, Pontus Brandt, Marc Kornblouth, Ralph McNutt, Dave McComas, and New Horizons team

Nonthermal energetic pickup ions (PUIs) are created in the heliosphere through charge exchange between solar wind ions and interstellar neutral atoms, and they play an essential role in understanding solar wind evolution in the outer heliosphere, as well as the structure and dynamics of the global heliosphere. New Horizons is now exploring the outer heliosphere and is the only spacecraft equipped with proper instruments to measure energetic PUIs in the outer heliosphere region. Its observations have shown that energetic PUIs dominate the internal pressure of the outer heliosphere, contribute substantially to the heating and slowing down of the solar wind, and mediate shock waves in the outer heliosphere. Some PUIs can turn into energetic neutral atoms (ENAs) via charge exchange with interstellar hydrogen, which can be detected by IBEX, CASSINI, and future IMAP spacecraft. ENA observations have provided global observations of our heliosphere and tremendously improved our knowledge about the heliosphere and its interaction with the Interstellar medium. In this talk, I will provide an overview of the energetic PUIs and their importance in the outer heliosphere.