Interplanetary particle transport simulation for warning system for aviation exposure to solar energetic particles

TL;DR

This paper presents a new simulation-based warning system for aviation exposure to solar energetic particles, modeling their transport in interplanetary space to predict intensity and spectrum near Earth.

Contribution

The authors developed a novel stochastic differential equation-based simulation code for SEP transport in interplanetary space, integrated into a warning system for aviation safety.

Findings

Simulation closely reproduces observed SEP intensity evolution.

The system can provide early warnings for solar energetic particle events.

Validated against real SEP event data.

Abstract

Solar energetic particles (SEPs) are one of the extreme space weather phenomena. A huge SEP event increases the radiation dose received by aircrews, who should be warned of such events as early as possible. We developed a warning system for aviation exposure to SEPs. This article describes one component of the system, which calculates the temporal evolution of the SEP intensity and the spectrum immediately outside the terrestrial magnetosphere. To achieve this, we performed numerical simulations of SEP transport in interplanetary space, in which interplanetary SEP transport is described by the focused transport equation. We developed a new simulation code to solve the equation using a set of stochastic differential equations. In the code, the focused transport equation is expressed in a magnetic field line coordinate system, which is a non-orthogonal curvilinear coordinate system. An inverse Gaussian distribution is employed as the injection profile of SEPs at an inner boundary located near the Sun. We applied the simulation to observed SEP events as a validation test. The results show that our simulation can closely reproduce observational data for the temporal evolution of particle intensity. By employing the code, we developed the WArning System for AVIation Exposure to Solar energetic particles (WASAVIES).