Speaker
Description
The observation of galactic cosmic ray (GCR) deuteron at the Earth has been done precisely with
the PAMELA and AMS02 space detectors and reported from July 2006 to September 2014 and
from May 2011 to April 2021, respectively. These observations span time frames that include solar
maximum and both minimum modulation conditions in the A > 0 and A < 0 magnetic field cycles
at rigidities between ~ 0.75 GV and ~ 19.5 GV. A surprise from AMS02 observation was that current
available GALPROP calculated deuteron local interstellar spectra (LIS) are unable to reproduce the
deuteron observations at rigidities above ~5 GV, and thus challenging the status quo regarding
their origin in the galaxy. In this study a comprehensive 3D numerical model and a set of diffusion
and drift coefficients, previously applied to a number of cosmic ray nuclei, together with a newly
estimated LIS for deuterons, are used to simulate the modulation of deuterons from July 2006 to
April 2021. The modelling results will be compared to observations made by PAMELA and AMS-02
detectors. This study will illustrate and discuss the effects due to different LISs and those caused by
the main modulation mechanisms on deuteron modulation at the Earth. Furthermore, differences
between the modulation of protons and deuterons at the Earth will be uncovered and highlighted.
