Energy-dependent cosmic-ray diffusion coefficient in the interstellar medium

Determine the functional form, normalization, and energy dependence of the interstellar cosmic-ray diffusion coefficient D(E) in the local interstellar medium to enable accurate modeling of diffused supernova-accelerated cosmic-ray spectra and resulting radiation dose profiles for generation ships.

Background

When computing the diffused spectrum of supernova-origin cosmic rays, the authors solve a diffusion equation and must specify the diffusion coefficient D(E). They highlight that D(E) is poorly constrained and adopt a first-order power-law approximation with a tunable index δ for their simulations.

Tighter empirical or theoretical constraints on D(E) are needed to reduce uncertainty in predicted radiation exposures from supernovae and to improve risk assessments for multi-generational spacecraft traversing interstellar space.