Comparison of space radiation GCR models to recent AMS data

Abstract

This paper is the third in a series of comparisons of American (NASA) and Russian (ROSCOSMOS) space radiation calculations. The present work focuses on calculation of fluxes of galactic cosmic rays (GCR), which are a constant source of radiation that constitutes one of the major hazards during deep space exploration missions for both astronauts/cosmonauts and hardware. In this work, commonly used GCR models are compared with recently published measurements of cosmic ray Hydrogen, Helium, and the Boron-to-Carbon ratio from the Alpha Magnetic Spectrometer (AMS). All of the models were developed and calibrated prior to the publication of the AMS data; therefore this an opportunity to validate the models against an independent data set.

Keywords: Alpha magnetic spectrometer; Galactic cosmic rays; Space radiation.

Figure 1:

(a) Models (histograms) compared to AMS Hydrogen flux data (Aguilar et al., 2015) (black circles) integrated from May 19, 2011 - November 26, 2013. (b) The ratio of each model results divided by AMS data. The error bars include uncertainties from the AMS data only. Ideally, the model ratios would be unity if they agreed perfectly with data.

Figure 2:

The same Hydrogen data (circles) and models (histograms) shown in Figure 1, but highlighting different parts of the GCR spectrum. (a) Fluxes plotted on a linear scale to emphasize the low energy part of the spectrum. (b) Fluxes scaled by T^2.7 to better visualize the higher energy part of the spectrum.

Figure 3:

(a) Models (histograms) compared to AMS Helium flux data (Aguilar et al., 2015a) (black circles) integrated from May 19, 2011 - November 26, 2013. (b) The ratio of each model results divided by AMS data. The error bars include uncertainties from the AMS data only.

Figure 4:

The same Helium data (circles) and models (histograms) shown in Figure 3, but highlighting different parts of the GCR spectrum. (a) Fluxes plotted on a linear scale to emphasize the low energy part of the spectrum. (b) Fluxes scaled by T^2.7 to better visualize the higher energy part of the spectrum.

Figure 5:

(a) Models (histograms) compared to the AMS Boron to Carbon ratio (Aguilar et al., 2016) (black circles) integrated from May 19, 2011 - May 26, 2016. (b) The ratio of each model results divided by AMS data. The error bars include uncertainties from the AMS data only. The SINP ratios for the highest energy bins extend off the plot.