A GPU-Computing Approach to Solar Stokes Profile Inversion

TL;DR

This paper introduces GENESIS, a GPU-accelerated genetic algorithm for fast, full-disc solar vector magnetic field mapping from Stokes polarization data, significantly improving computational efficiency.

Contribution

It presents a novel GPU-based genetic algorithm approach for solar Stokes profile inversion, enabling rapid, full-disc vector magnetogram generation.

Findings

GPU-accelerated inversion is significantly faster than CPU-based methods.

Full-disc vector magnetograms can be produced in real-time.

The method effectively exploits parallelism in the inversion process.

Abstract

We present a new computational approach to the inversion of solar photospheric Stokes polarization profiles, under the Milne-Eddington model, for vector magnetography. Our code, named GENESIS (GENEtic Stokes Inversion Strategy), employs multi-threaded parallel-processing techniques to harness the computing power of graphics processing units GPUs, along with algorithms designed to exploit the inherent parallelism of the Stokes inversion problem. Using a genetic algorithm (GA) engineered specifically for use with a GPU, we produce full-disc maps of the photospheric vector magnetic field from polarized spectral line observations recorded by the Synoptic Optical Long-term Investigations of the Sun (SOLIS) Vector Spectromagnetograph (VSM) instrument. We show the advantages of pairing a population-parallel genetic algorithm with data-parallel GPU-computing techniques, and present an overview of the Stokes inversion problem, including a description of our adaptation to the GPU-computing paradigm. Full-disc vector magnetograms derived by this method are shown, using SOLIS/VSM data observed on 2008 March 28 at 15:45 UT.