Browsing by Author "Franssila, Fanni"

Magnetic reconnection is a phenomenon occurring in plasma and related magnetic fields when magnetic field lines break and rejoin, leading to the release of energy. Magnetic reconnections take place, for example, in the Earth’s magnetosphere, where they can affect the space weather and even damage systems and technology on and around the Earth. Another site of interest is in fusion reactors, where the energy released from reconnection events can cause instability in the fusion process. So far, 2D magnetic reconnection has been widely studied and is relatively well-understood, whereas the 3D case remains more challenging to characterize. However, in real-world situations, reconnection occurs in three dimensions, which makes it essential to be able to detect and analyse 3D magnetic reconnection, as well. In this thesis, we examine what potential signs of 3D magnetic reconnection can be identified from the topological elements of a magnetic vector field. To compute the topological elements, we use the Visualization Toolkit (VTK) Python package. The topology characterizes the behaviour of the vector field, and it may reveal potential reconnection sites, where the topological elements can change as a result of magnetic field lines reconnecting. The magnetic field data used in this thesis is from a simulation of the nightside magnetosphere produced using Vlasiator. The contributions of this thesis include analysis of the topological features of 3D magnetic reconnection and topological representations of nightside reconnection conditions to use in potential future machine learning approaches. In addition, a modified version of the VTK function for computing the critical points of the topology is created with the purpose of gearing it more towards magnetic vector fields instead of vector fields in general.