Prediction of Solar Proton Event Fluence spectra from their Peak flux spectra

Sigiava Aminalragia-Giamini,Ingmar Sandberg,Angels Aran,Athanasios Papaioannou,Rami Vainio,Evangelos Paouris,Anastasios Anastasiadis,Mark Dierckxsens,Miikka Paassilta,Georgios Vasalos,Antonis Tsigkanos,Constantinos Papadimitriou,Piers Jiggens

doi:10.1051/swsc/2019043

Abstract

Solar Proton Events (SPEs) are of great importance and significance for the study of Space Weather and Heliophysics. These populations of protons are accelerated at high energies ranging from a few MeVs to hundreds of MeVs and can pose a significant hazard both to equipment on board spacecrafts as well as astronauts as they are ionizing radiation. The ongoing study of SPEs can help to understand their characteristics, relative underlying physical mechanisms, and help in the design of forecasting and nowcasting systems which provide warnings and predictions. In this work, we present a study on the relationships between the Peak Flux and Fluence spectra of SPEs. This study builds upon existing work and provides further insights into the characteristics and the relationships of SPE Peak flux and Fluence spectra. Moreover it is shown how these relationships can be quantified in a sound manner and exploited in a simple methodology with which the Fluence spectrum of an SPE can be well predicted from its given Peak spectrum across two orders of magnitude of proton energies, from 5 MeV to 200 MeV. Finally it is discussed how the methodology in this work can be easily applied to forecasting and nowcasting systems.

Highlights

Solar Energetic Particle (SEP) events and their proton component (Solar Proton Events, SPEs) are some of the most hazardous phenomena of space weather, they contain populations of ionizing radiation and as such they can present dangers for the increasingly complex electronics on board spacecrafts such as those of commercial satellites and sensitive instruments of scientific missions
We have investigated in depth the relationships of Peak and Fluence spectra in SPEs using the SEPEM RDS v2.0 differential proton flux intensity dataset and two SPE Events lists, the SEPEM Reference Event List and the Event list used in the FORecasting Solar Particle Events and Flares (FORSPEF) system
By fitting the Peak and Fluence spectra with analytical exponential cut-off power-law functions it is found that this relationship is directly reflected in the close similarity of the spectral indexes and the scaling relationship between the spectral intensities

Summary

Introduction

Solar Energetic Particle (SEP) events and their proton component (Solar Proton Events, SPEs) are some of the most hazardous phenomena of space weather, they contain populations of ionizing radiation and as such they can present dangers for the increasingly complex electronics on board spacecrafts such as those of commercial satellites and sensitive instruments of scientific missions. This is even more important for missions outside the Earth’s protective magnetosphere for satellites in the Sun–Earth Lagrangian Points as well as missions to Mars since SPEs can reach into the interplanetary space and still retain much of their hazardous potential (Jiggens et al, 2019). Space Weather Space Clim. 2020, 10, 1 system (Papaioannou et al, 2015, 2018), the Warning System for Aviation Exposure to SEP (WASAVIES) (Kataoka et al, 2014) and WASAVIES – Earth Orbit (WASAVIES-EO) (Sato et al, 2019) systems, the Relativistic Electron Alert System for Exploration (RELeASE) (Posner, 2007; Malandraki & Crosby, 2018), the Empirical model for Solar Proton Events Real

Methods

Results

Conclusion