Solar neutrons, an useful tool to study particle acceleration in the solar atmosphere

Particle acceleration inside the solar atmosphere remains not fully understood. Although several mechanisms have been proposed, a widely accepted framework is still lacking. Understanding these processes is crucial not only for studying particle acceleration itself but also for providing deeper insights into the solar explosive events. The most natural approach to studying particle acceleration mechanisms is by analysing the ionised particles that escape into the heliosphere, which may eventually reach the Earth. Additionally, a strong flux of these particles is emitted, facilitating their study. Nevertheless, its main drawback lies in the difficulty of precisely determining ionised particles’ trajectories, as they are affected by the electromagnetic field present in the heliosphere. Solar neutrons (SNs) are produced by the collisions between accelerated particles, mainly protons and 𝛼, and nuclei present in the solar atmosphere. A portion of the kinetic energy of the former is transferred to the SNs, and as a result, some of them escape the solar atmosphere and eventually reach the Earth. Since SNs do not experience the Lorentz force, they propagate undisturbed through the magnetosphere, following a straight trajectory. This offers an alternative approach for analysing particle acceleration in the solar atmosphere, independent of the magnetosphere. SN production has been simulated, taking into consideration various parameters concerning the solar atmosphere. These simulations involved not only the collisions but also the possible outcomes for the neutrons, which include being lost to the Sun’s interior, capture with the subsequent emission of gamma-rays, or escaping. Finally, we evaluate the consequences of gamma-rays and escaping SNs on Earth, aiming to gain deeper insight into the solar atmosphere.