2016/04/30 by P. Swaczyna, Paweł Swaczyna, M. Bzowski +3 · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Computational physics #Energetic neutral atom #Geometry #Heliosphere #Ionosphere and magnetosphere dynamics #Nuclear physics #Physics #Plasma #Ribbon #Sky #Solar and Space Plasma Dynamics #Solar wind #astro-ph.SR
paper · pdf · doi:10.3847/0004-637x/827/1/71
published as ApJ 827 (2016), 71 · 14 pages, 8 figures, 1 table, v3: corrected caption to Figure 3
openalex publication_date 2016/08/09 · arxiv created 2018/01/29 · arxiv updated 2018/01/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
ABSTRACT Observations of energetic neutral atoms (ENAs) allow for remote studies of the condition of plasma in the heliosphere and the neighboring local interstellar medium. The first results from the Interstellar Boundary Explorer ( IBEX ) revealed an arc-like enhancement of the ENA intensity in the sky, known as the ribbon. The ribbon was not expected from the heliospheric models prior to the launch of IBEX . One proposed explanation for the ribbon is the mechanism of secondary ENA emission. The ribbon reveals energy-dependent structure in the relative intensity along its circumference and in its position. That is, the geometric center of the ribbon varies systematically by about 10° in the energy range 0.7–4.3 keV. Here, we show by analytical modeling that this effect is a consequence of the helio-latitudinal structure of the solar wind reflected in the secondary ENAs. Along with a recently measured distance to the ribbon’s source just beyond the heliopause, our findings support the connection of the ribbon with the local interstellar magnetic field by the mechanism of secondary ENA emission. However, the magnitude of the center shift in the highest IBEX energy channel is much larger in the observations than expected from the modeling. This may be due to another, not currently recognized, process of ENA generation.