Distinguishing Tests of the Interstellar Boundary Explorer Ribbon through Numerical Modeling: Current Results and Future Prospects

Abstract:

The Interstellar Boundary EXplorer (IBEX) "ribbon" is a unique feature of enhanced energetic neutral atom (ENA) flux encircling the sky. Ever since its discovery, numerous interpretations have been proposed to explain the ribbon's existence, with sophisticated models and simulations attempting to explain key characteristics of the ribbon, including its intensity, spatial and spectral structure, and evolution over time. Although the ribbon's origin is still unknown, the leading theory is the so-called "secondary ENA" mechanism, in which primary ENAs from inside the heliosphere undergo two charge-exchange events outside the heliopause, producing secondary ENAs which may come back inside the heliosphere and be detected by IBEX. While the leading hypothesis for the generation of the ribbon ("secondary ENA" mechanism) appears to explain several key characteristics, modeling efforts are becoming under-constrained by current measurement capabilities. In this talk, I present an analysis of key measurement parameters needed to test and differentiate hypotheses of the ribbon in models and simulations (e.g., spectral range and resolution, angular resolution, and temporal baseline of observations). Understanding these parameters and their importance for identifying and interpreting the physical processes that generate the ribbon are critical for the Interstellar Mapping and Acceleration Probe (IMAP).