A Massively Parallel Time-Domain Coupled Electrodynamics-Micromagnetics Solver

TL;DR

This paper introduces a high-performance, scalable coupled electrodynamics-micromagnetics solver that accurately models signals in microelectronic circuits using advanced numerical methods and is optimized for exascale supercomputing architectures.

Contribution

It presents a novel second-order accurate temporal coupling scheme integrated into a scalable FDTD and LLG-based solver, optimized for GPU and multicore supercomputers.

Findings

Achieved 59x speedup on GPU systems.

Demonstrated scalability on NERSC supercomputers.

Validated simulations of waveguides and tunable filters.

Abstract

We present a new, high-performance coupled electrodynamics-micromagnetics solver for full physical modeling of signals in microelectronic circuitry. The overall strategy couples a finite-difference time-domain (FDTD) approach for Maxwell's equations to a magnetization model described by the Landau-Lifshitz-Gilbert (LLG) equation. The algorithm is implemented in the Exascale Computing Project software framework, AMReX, which provides effective scalability on manycore and GPU-based supercomputing architectures. Furthermore, the code leverages ongoing developments of the Exascale Application Code, WarpX, primarily developed for plasma wakefield accelerator modeling. Our novel temporal coupling scheme provides second-order accuracy in space and time by combining the integration steps for the magnetic field and magnetization into an iterative sub-step that includes a trapezoidal discretization for the magnetization. The performance of the algorithm is demonstrated by the excellent scaling results on NERSC multicore and GPU systems, with a significant (59x) speedup on the GPU using a node-by-node comparison. We demonstrate the utility of our code by performing simulations of an electromagnetic waveguide and a magnetically tunable filter.