Heliospheric Transport of Neutron-Decay Protons

TL;DR

This paper presents new simulations of how energetic protons from neutron decay, produced in solar flares, spread through space, suggesting they can be detected over wide regions and times, especially with multiple spacecraft.

Contribution

It introduces novel simulations of neutron-decay proton transport, highlighting their detectability over broad regions and the potential for multi-spacecraft observations during solar cycles.

Findings

Neutron-decay protons are produced over a wide spatial region.

Spacecraft closer to the Sun observe significantly higher intensities.

Multiple spacecraft can detect these protons over different longitudes.

Abstract

We report on new simulations of the transport of energetic protons originating from the decay of energetic neutrons produced in solar flares. Because the neutrons are fast-moving but insensitive to the solar wind magnetic field, the decay protons are produced over a wide region of space, and they should be detectable by current instruments over a broad range of longitudes for many hours after a sufficiently large gamma-ray flare. Spacecraft closer to the Sun are expected to see orders-of magnitude higher intensities than those at the Earth-Sun distance. The current solar cycle should present an excellent opportunity to observe neutron-decay protons with multiple spacecraft over different heliographic longitudes and distances from the Sun.