Characterizing the Motion of Solar Magnetic Bright Points at High Resolution

TL;DR

This study uses high-resolution simulations to analyze the motion of solar magnetic bright points, providing insights into wave excitation and energy transport in the solar atmosphere, with predictions for upcoming DKIST observations.

Contribution

It introduces a simulation-based power spectrum of bright-point motion at high resolution, supporting observational data and exploring the effects of granulation and turbulence.

Findings

Power spectrum slightly higher than observations but shape consistent

Supports two-population granule size distribution

Passive tracers show similar motion spectrum

Abstract

Magnetic bright points in the solar photosphere, visible in both continuum and G-band images, indicate footpoints of kilogauss magnetic flux tubes extending to the corona. The power spectrum of bright-point motion is thus also the power spectrum of Alfven wave excitation, transporting energy up flux tubes into the corona. This spectrum is a key input in coronal and heliospheric models. We produce a power spectrum of bright-point motion using radiative magnetohydrodynamic simulations, exploiting spatial resolution higher than can be obtained in present-day observations, while using automated tracking to produce large data quantities. We find slightly higher amounts of power at all frequencies compared to observation-based spectra, while confirming the spectrum shape of recent observations. This also provides a prediction for observations of bright points with DKIST, which will achieve similar resolution and high sensitivity. We also find a granule size distribution in support of an observed two-population distribution, and we present results from tracking passive tracers which show a similar power spectrum to that of bright points. Finally, we introduce a simplified, laminar model of granulation, with which we explore the roles of turbulence and of the properties of the granulation pattern in determining bright-point motion.