PhD Thesis Projects/Papers
PhD Thesis Projects/Papers
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Project 3
Project 3
A Statistical Analysis on the Longitudinal Spread of SEPs Using the Spatial Analysis Tool
A Statistical Analysis on the Longitudinal Spread of SEPs Using the Spatial Analysis Tool
Upcoming, watch this space to find out more!
Second Paper
Second Paper
Characterizing Longitudinal SEP Spread with Gaussian Fits of Multi-spacecraft Observations
Characterizing Longitudinal SEP Spread with Gaussian Fits of Multi-spacecraft Observations
This project is in the process of being summarized and submitted, but preliminary results have been presented as a poster which you can download.
JTL_PhysicsDaysPoster.pdfOpen Access Tool
Open Access Tool
Spatial Distribution Analysis of Solar Particles
Spatial Distribution Analysis of Solar Particles
This tool downloads SEP intensity-time series data (and location data) from various different spacecraft and visualises the SEP distribution by fitting Gaussian curves to the intensity-position data over time.
Access the tool through the SOLER Project Jupyter Hub.
This tool forms part of the SEP tools within the SOLER Horizon Europe project and can be cited using the Zenodo listing. A summary of all the tools built under the SOLER project umbrella have been summarised into an upcoming paper (currently available on arXiv).
Lang_SOLERposter_A0.pdfA Detailed Survey of the Parallel Mean Free Path of Solar Energetic Particle Protons and Electrons
A Detailed Survey of the Parallel Mean Free Path of Solar Energetic Particle Protons and Electrons
Summary figure taken from the paper below of all the parallel mean-free path results for both electrons and protons as a function of rigidity. These results are compared to the 'valley' pattern mentioned by Dröge (2000) and the Palmer (1982) consensus values, as well as individual values from other papers (marked by the initial of the first authors of those papers). To find details of the different markers, please see the paper.
In this work, more than a dozen solar energetic particle (SEP) events are identified where the source region is magnetically well connected to at least one spacecraft at 1 au.
The observed intensity–time profiles, for all available proton and electron energy channels, are compared to results computed using a numerical one-dimensional SEP transport model in order to derive the parallel mean free paths (pMFPs) as a function of energy (or rigidity) at 1 au.
These inversion results are then compared to theoretical estimates of the pMFP, using observed turbulence quantities with observationally motivated variations as input. For protons, a very good comparison between inversion and theoretical results is obtained.
It is shown that the observed inter-event variations in the inversion pMFP values can be explained by natural variations in the background turbulence values. For electrons, there is relatively good agreement with pMFPs derived assuming the damping model of dynamical turbulence, although the theoretical values are extremely sensitive to the details of the turbulence dissipation range, which themselves display a high level of variation.
To read the full paper: Lang et al. (2024) The Astrophysical Journal, 971 105
A figure taken from my Masters dissertation that highlights all the events that were included in the catalogue. Each color corresponds to a new solar event, each shape corresponds to a specific spacecrafts observations, and the black line corresponds to the average sunspot number over 30 years. The markers denote the resulting parallel mean-free path value as seen in the right y-axis. This figure was created using the SunPy Python package (https://sunpy.org/).
MSc Thesis Project
MSc Thesis Project
Observing the Unobservable by Inverting Solar Energetic Particle Events
Observing the Unobservable by Inverting Solar Energetic Particle Events
Abstract
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 ad the best-fit results are found using the coefficient of determination goodness-of-fit statistic. The 1D transport model utilized 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 Dröge (2000), Engelbrecht and Moloto (2021), and Teufel & Schlickeiser (2002).
To read the full dissertation: NWU Repository
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