Observing the Unobservable by Inverting Solar Energetic Particle Events

Abstract

The mechanisms behind solar energetic particle (SEP) transport have been investigated for decades in the development of accurate and predictive space weather models. This dissertation investigates certain potential influences on the transport parameters that the SEPs experience within the inner heliosphere (< 1 AU). Inverting SEP events involves overlaying model simulations to existing observational data to an accurate fit; this process provides the transport parameters from the model as a result. To introduce the process of fitting model simulations to observational data, synthetic data are created and the best-fit results are found using the coefficient of determination (CoD) goodness-of-fit statistic. The one-dimensional (1D) transport model utilised in this project requires that observations of SEP events be recorded by instruments on magnetically well-connected spacecraft. By modelling the GLE#73 event of 28 October 2021, this process of finding observations for magnetically well-connected instruments is introduced. The final transport parameters are then investigated to find potential trends as well as compare them to previously determined estimates. It was found that the results presented in this project compared well with already defined trends, such as those presented by Dr¨oge (2000), Engelbrecht and Moloto (2021), and Teufel and Schlickeiser (2002).