Solar energetic particle events: trajectory analysis and flux reconstruction with PAMELA

TL;DR

This paper presents a novel method for analyzing Solar Energetic Particles using PAMELA satellite data, including trajectory simulations and flux reconstruction, demonstrated on the May 17, 2012 event.

Contribution

It introduces new analysis techniques for SEP energy spectra and anisotropy estimation based on detailed trajectory simulations in Earth's magnetosphere.

Findings

Successful reconstruction of SEP flux and anisotropy for the May 17, 2012 event.

Enhanced understanding of SEP propagation and magnetic field interactions.

Methodology applicable to future SEP event analyses.

Abstract

The PAMELA satellite experiment is providing first direct measurements of Solar Energetic Particles (SEPs) with energies from about 80 MeV to several GeV in near-Earth space, bridging the low energy data by other space-based instruments and the Ground Level Enhancement (GLE) data by the worldwide network of neutron monitors. Its unique observational capabilities include the possibility of measuring the flux angular distribution and thus investigating possible anisotropies. This work reports the analysis methods developed to estimate the SEP energy spectra as a function of the particle pitch-angle with respect to the Interplanetary Magnetic Field (IMF) direction. The crucial ingredient is provided by an accurate simulation of the asymptotic exposition of the PAMELA apparatus, based on a realistic reconstruction of particle trajectories in the Earth's magnetosphere. As case study, the results for the May 17, 2012 event are presented.