Year: 2026
Type: article
Abstract: Solar energetic particles (SEPs) are charged particles, such as protons and electrons, that have been accelerated at or near the Sun by eruptive phenomena to high energies.SEPs are known to pose a serious hazard to both electric equipment and biological tissue in space because of their ionizing effect, which is why the study of SEP events is of great importance.SEP events are characterized by signifcantly elevated energetic particle intensity levels.The starting time of an SEP event, which is called the onset time, is a crucial piece of information in relating the in-situ measurements of increased intensity to the remote observation of the solar eruption that caused the acceleration of the observed particles.While different methods for determining the onset time have been developed in the past, the temporal uncertainty of the onset time is something that has not been evaluated in a rigorous and methodological way by these methods.In this dissertation, different analysis methods for SEP events are presented.Established onset-determination methodology is refned and combined in a novel way with statistical methods to create an onset-determination method that yields the most probable onset time regardless of the used time resolution, and evaluates the temporal uncertainty of the onset time.Furthermore, extensive data-analysis software packages that handle downloading, visualizing, analysis, and result exportation of energetic particle intensity data were developed.These software packages, called SEPpy and PyOnset, were released as open-source software to the scientifc community.In addition to energetic particle intensity data, methodology concerning the magnetic connectivity between the Sun and an observer is also considered.A software tool that automatically determines the positions of the desired observers and employs a Parker spiral model to evaluate the connectivity, called Solar-MACH, was developed.Solar-MACH is able to display the confguration of heliospheric observes in relation to Sun in 2D and 3D, and is also able to combine the Parker model for the heliospheric magnetic feld with the potential feld source surface model for the coronal magnetic feld to give more precise estimates of magnetic connectivity between the Sun and an observer.
Source: UTUPub (University of Turku)
Author: Vanha-Similä Maria
Language: Finnish
Subfield: General Arts and Humanities
Field: Arts and Humanities
Domain: Social Sciences
Open Access status: green
OpenAlex ID: W7220815381