Pinpointing Cosmic Ray Propagation With The AMS-02 Experiment

TL;DR

This paper explores how upcoming AMS-02 measurements of cosmic ray ratios can precisely constrain simple propagation models, but face limitations with more complex scenarios involving inhomogeneity and stochasticity.

Contribution

It demonstrates that AMS-02 data can accurately determine parameters of simple cosmic ray propagation models and highlights challenges in constraining complex models.

Findings

High-precision parameter determination for simple models

Limited constraints on complex propagation scenarios

Projected AMS-02 data will significantly improve cosmic ray understanding

Abstract

The Alpha Magnetic Spectrometer (AMS-02), which is scheduled to be deployed onboard the International Space Station later this year, will be capable of measuring the composition and spectra of GeV-TeV cosmic rays with unprecedented precision. In this paper, we study how the projected measurements from AMS-02 of stable secondary-to-primary and unstable ratios (such as boron-to-carbon and beryllium-10-to-beryllium-9) can constrain the models used to describe the propagation of cosmic rays throughout the Milky Way. We find that within the context of fairly simple propagation models, all of the model parameters can be determined with high precision from the projected AMS-02 data. Such measurements are less constraining in more complex scenarios, however, which allow for departures from a power-law form for the diffusion coefficient, for example, or for inhomogeneity or stochasticity in the distribution and chemical abundances of cosmic ray sources.