Global ENA Images
Global ENA images easily differentiate between types of interactions at the termination shock, while detailed energy spectra as a function of direction provide information about 3D configuration of the shock and energy partition of the ions at the shock (Question I). Differences between the upstream and downstream directions and more subtle asymmetries in the global images enable the determination of the solar wind flow patterns beyond the termination shock (Question III).
ENA Energy Spectra
ENA energy spectra are direct measures of the solar wind, pickup ions (Science Questions 1 and 3), and energetic protons beyond the Termination Shock (Science Question 2). Above 1 keV, these ENA energy spectra provide information about how the energetic particle pressure modifies the Termination Shock and what types of injection processes may be at work there (Science Question 1). Graph: Predicted ENA distributions near heliospheric nose for strong (black) and weak (green) TS [Gruntman et al., 2001]. ENAs >1 keV are accelerated inner heliosheath protons based on projecting observed distributions beyond Termination Shock. (Science Questions 1, 2 and 3)
Interstellar Neutral Oxygen
The first direct measurements of filtered interstellar neutral oxygen provide information about the speed, direction, and temperature of the interstellar oxygen inside the termination shock and provide information about the interstellar interaction further out, beyond the heliopause (Question IV).