Modeling and Simulation Group Meeting
Capturing Multi-Scale Phenomena in Simulations of Pulsars and Oceans
Speaker: Hannah Klion, CCSE Berkeley National Lab
Location: Warren Weaver Hall 202
Date: Thursday, October 24, 2024, 12:30 p.m.
Synopsis:
In many astrophysical and geophysical systems, small-scale processes drive global dynamics. The naive approach to simulating these systems – resolving small-scale processes in the entire large domain – can be computationally infeasible. I will discuss my work toward high-accuracy, multi-scale simulations of two such systems: the environments around pulsars and Earth’s oceans. Relativistic magnetic reconnection is a source of non-thermal particle acceleration in many high-energy, plasma-dominated, astrophysical systems, such as pulsars and black holes. However, it operates at spatial scales millions of times smaller than the pulsar itself, so fully capturing plasma processes in an unscaled global domain is not feasible. To complement scaled global simulations, I have focused on small box simulations of reconnection where the processes are accurately captured. However, these are still computationally expensive. I will discuss my work using the GPU-accelerated PIC code WarpX to explore the accuracy and potential performance benefits of advanced computational techniques, such as mesh refinement, for global pulsar and local reconnection simulations. I will also discuss my work on REMORA, a new performance-portable regional ocean model. Small-scale (<1km) processes are expected to be important to global oceanic flows, but cannot be captured in global ocean simulations. REMORA will couple to global ocean simulations in order to add refinement in regions of particular interest. Its capabilities, such as mesh refinement and tracer particles, also make it a flexible standalone tool for the study of hydrological processes. I will discuss progress toward these goals as well as future directions.