Browsing by Author "Tähtinen, Sara"

Magnetic reconnection is a process occurring in, e.g., space plasmas, that allows rapid changes of magnetic field topology and converts magnetic energy to thermal and non-thermal plasma energy. Especially solar flares are good examples of explosive magnetic energy release caused by magnetic reconnection, and it has been estimated that 50% of the total released energy is converted to the kinetic energy of charged particles. In spite of being such an important process in astrophysical phenomena, the theory and the mechanisms behind magnetic reconnection are still poorly understood. In this thesis, the acceleration of electrons in a two-and-half dimensional magnetic reconnection region with solar flare plasma conditions is studied using numerical modeling. The behavior of electrons are determined by calculating the trajectories of all particles inside a simulation box. The equations of motion are solved by using a particle mover called Boris method. The aim of this work is to better understand the acceleration of non-thermal electrons, and, for example, to explain how the inflow speed affects the final energy of the particles, what part of the reconnection area the most energetic electrons come from and how the scattering frequencies changes the energy spectra of the electrons. The focus of this thesis lies in numerical modeling, but all the relevant physics behind this subject are also briefly explained. First the basics of plasma physics are introduced, and leading models of magnetic reconnection are presented. Then the simulation setup and reasonable values for simulation parameters are defined and results of the simulations are discussed. Based on these, conclusions are drawn.