AMS Observations of Light Cosmic Ray Isotopes and Implications for their Production in the Galaxy

TL;DR

This paper analyzes cosmic ray light isotope data from AMS-01 to understand their galactic origin and propagation, highlighting the role of astrophysical and nuclear uncertainties in modeling.

Contribution

It compares AMS-01 measurements with propagation models, emphasizing the impact of nuclear cross-section uncertainties on predictions.

Findings

Data well described by diffusive-reacceleration model

Astrophysical uncertainties reduced with future data

Nuclear uncertainties limit model accuracy

Abstract

Observations of light isotopes in cosmic rays provide information on their origin and propagation in the Galaxy. Using the data collected by AMS-01 in the STS- 91 space mission, we compare the measurements on 1H, 2H, 3He and 4He with calculations for interstellar propagation and solar modulation. These data are described well by a diffusive-reacceleration model with parameters that match the B/C ratio data. Close comparisons are made within the astrophysical con- straints provided by the B/C data and within the nuclear uncertainties arising from the production cross sections. Astrophysical uncertainties are expected to be dramatically reduced by future data, but nuclear uncertainties may rep- resent a serious limitation of the model predictions. A diagnostic test for the reliability of the models is given by ratios such as 2H/3He, 6Li/7Li or 10B/11B.