In pursuit of the low-energy Solar neutron flux

TL;DR

This paper models low-energy solar neutron flux considering CME effects, finding narrow and fast CMEs significantly influence neutron production, with flux predictions aligning with previous observations.

Contribution

It introduces a CME-width scaling factor into neutron flux models, highlighting the impact of specific CME characteristics on solar neutron production.

Findings

Narrow and fast CMEs are key contributors to neutron flux.

Predicted neutron flux at 1 AU is 5-49 neutrons cm$^{-2}$ s$^{-1}$.

Total neutron flux over 4 hours accounts for 10.23% of observed flux.

Abstract

Understanding the origin of low-energy solar neutrons flux is crucial for probing solar energetic processes and neutron transport mechanisms in interplanetary space. This study investigates the role of coronal mass ejections (CMEs) in modulating the low-energy solar neutrons. The neutron flux is modeled by incorporating a CME-width scaling factor into existing neutron fluence models. Our analysis, based on CME data from the SECHHI COR2 database during the DANSON experiment (2016-10-27 to 2017-03-17), identified narrow-width (20$^\circ$ $<$ $\alpha$ $<$ 80$^\circ$) and fast (v $>$ 800 km/s) CMEs as key contributors to neutron production. The revised model predicts a neutron flux of 5 - 49 neutrons cm$^{-2}$ s$^{-1}$ at 1 AU for a neutron travel time of 1.66 hours, aligning with previous reports. Additionally, the estimated total flux of 2.45 MeV neutrons over a 4-hour period accounts for 10.23\% of DANSON's total flux. These findings suggest that CME-driven mechanisms may significantly influence the low-energy solar neutron flux. More observational efforts are needed to refine neutron flux estimates and improve background subtraction techniques for spaceborne neutron detectors.