Péter Maller\(^1\), Emese Forgács-Dajka\(^1\), Dániel Berényi\(^2\)

1. Eötvös Loránd University
2. Freelancer

Abstract: The main goal of the project is to parallelize a well-known Babcock-Leighton solar dynamo model, which can be used to study the development of the Sun's global magnetic field, thus solar activity. The prediction of solar activity is still challenging, as a quasi-periodic, stochastic process is in the background. In addition, the dynamo, which describes the underlying physics, is still one of the great unsolved problems of astrophysics. Of course, this does not mean that we do not have ideas or even models regarding the development of the magnetic field, but these models require further investigation and development.

The numerical code we created was based on an earlier Fortran language program, developed several decades ago, the modernization of which was motivated by several things: on the one hand, there are redundancies in the code written by many people over a long period of time, but also parts that are apparently redundant, on the other hand, further development is difficult due to the structure of the code. Thus, our first goal was to optimize and refactor the previous code, for which we chose the C programming language. Next, we want to parallelize the code, for which we use the CUDA framework. The reduction in running time achieved by parallelization enables comprehensive analyses: we can examine the development of several components of the magnetic field at a higher spatial resolution, but we can also map the parameter space of the model. Among our goals is the comparison of different numerical methods, such as ADI (Alternating-Direction Implicit) and FTCS (Forward Time-Centered Space). Overall, during the implementation of the project, we want to explore different options in order to choose the right compromise solution in terms of performance, accuracy and future improvements.