IBEX ribbon

In this model, a ring distribution of pick-up ions in the local interstellar magnetic field leads to the production of ribbon ENAs, assuming inefficient isotropization.

[2] A second theory by Schwadron & McComas (2013), proposes that the ribbon results from temporary containment of newly ionized atoms in a "retention" region in the local interstellar medium.

[2] Xu and Liu (2023) propose that magnetohydrodynamic (MHD) turbulence in the very local interstellar medium plays a key role in forming the IBEX ribbon through a mechanism called mirror diffusion.

[4] The width of the IBEX ribbon (approximately 20° at 1 keV) is determined by two factors: the range of pitch angles where turbulent mirroring is effective and the wandering of magnetic field lines caused by Alfvénic modes.

For energies below 1.7 keV, the ribbon's intensity recovered near the nose direction and up to 25° southward, but not at mid and high ecliptic latitudes, which fell in similar phases of solar cycles 23 and 24.

The recovery was first observed in the southern regions where the heliosphere's boundaries are closest to the Sun, consistent with models predicting different response times based on the distance traveled by the particles.

These characteristics provide key constraints for models of the ribbon's formation and its relationship to the broader heliosphere-interstellar medium interaction, though the exact physical mechanisms involved are still uncertain.

[8] With IBEX continuing its mission, future studies aim to compare its results with data from NASA’s Interstellar Mapping and Acceleration Probe (IMAP), which is expected to provide higher-resolution ENA measurements.

The IBEX ribbon on a 2009 all-sky map
High-energy map of the heliosphere
The IBEX spacecraft
The ribbon of ENA emissions seen in the IBEX map.
(a), (b) Ribbon-centered maps showing all-sky energetic neutral atom (ENA) fluxes at five IBEX-Hi energies for 2009 and 2019. (c), (d) Separated Ribbon-only maps for 2009 processed using maps from (a), (b) and the Ribbon separation method of Swaczyna et al. (2022). Labels mark the directions of upwind interstellar inflow (nose), and the Voyager spacecraft (V1 and V2). [ 5 ]
A juxtapositive graph of Interstellar Probe 's potential flyby speed after Jupiter, year of flyby, potential flyby targets, and the IBEX ribbon.