Topic: Computational Plasma Group Meeting

https://zoom.us/j/91974802468

Meeting ID: 919 7480 2468

Passcode: 032995

Abstract: Elliptic and parabolic partial differential equations often appear in astrophysical applications. As the information propagates instantaneousy in an elliptic PDE such as the Poisson equation for self-gravity, it requires global communication to get a consistent solution. A similar problem arises in a parabolic PDE such as the radiation diffusion when the speed of light is much larger than the typical dynamical speed in the system. Such systems are computationally more difficult to solve efficiently, and various solutions are proposed. The Multigrid method is one of the most efficient solver at least for self-gravity, and can be applicable to various physical processes. In this talk, I will summarize the concept of the Multigrid solver and its implementation for the self-gravity solver in the Athena++ code.

Speaker introduction: Prof. Kengo Tomida is an associate professor at the Astronomical Institute at Tohoku University. He obtained his B.S. from Kyoto University in 2007, and PhD from Graduate University for Advanced Studies in 2012. He spent 3.5 years at Department of Astrophysical Sciences, Princeton University as a JSPS fellow and a TCAN postdoc. He became an assistant professor in Theoretical Astrophysics Group at Osaka University in 2015, and he started the current position in 2020. His research interests include star/disk/planet formation and computational astrophysics. He is one of the main developers of the Athena++ public MHD code and has developed its adaptive mesh refinement, new parallelization scheme based on TaskList, self-gravity module based on the Multigrid method, and so on.