Transport of energetic charged particles in reservoirs behind CME-driven shock waves

Abstract

Long duration $\gamma$-ray flares (LDGRFs) are extended events of elevated $\gamma$-radiation (>100 MeV) measured from the Sun. The underlying cause for LDGRF formation is currently not well understood, and the purpose of this thesis was to create a simple Monte Carlo simulation model to test whether charged particles in the reservoirs behind a CME-driven shock waves could provide insights into the creation of LDGRFs. The hypothesis was that these charged particles are accelerated to high enough momenta, so that if precipitated back to the Sun, they would cause $\gamma$-radiation when colliding with the ambient Solar plasma. The model was based on Parker's transport equation, and the simulation was done by treating the Parker equation as a Stochastic Differential Equation (SDE) and solving the SDE using the Euler-Maruyama (EM) method. We find that the model successfully explains a subset of LDGRFs, which last up to a couple of hours at most. The model does not, however, provide explanation for even longer duration LDGRFs, some of which can last up to 20 hours. Parameter tuning is needed to further investigate if the model can explain the aforementioned longer lasting LDGRFs.