Dynamics of isolated magnetic bright points derived from Hinode/SOT G-band observations

TL;DR

This study analyzes the motion and lifetime of magnetic bright points in the solar photosphere using Hinode/SOT G-band data, providing corrected velocity and lifetime distributions crucial for understanding solar magnetic dynamics and coronal heating.

Contribution

Developed an automatic algorithm to accurately track MBPs and corrected their velocity and lifetime distributions for sampling effects, advancing solar magnetic field analysis.

Findings

Mean MBP lifetime of 2.50 minutes

Velocity distribution follows a Rayleigh function with coefficient 1.62 km/s

Velocity components are Gaussian, and lifetime distribution is exponential.

Abstract

Small-scale magnetic fields in the solar photosphere can be identified in high-resolution magnetograms or in the G-band as magnetic bright points (MBPs). Rapid motions of these fields can cause magneto-hydrodynamical waves and can also lead to nanoflares by magnetic field braiding and twisting. The MBP velocity distribution is a crucial parameter for estimating the amplitudes of those waves and the amount of energy they can contribute to coronal heating. The velocity and lifetime distributions of MBPs are derived from solar G-band images of a quiet sun region acquired by the Hinode/SOT instrument with different temporal and spatial sampling rates. We developed an automatic segmentation, identification and tracking algorithm to analyse G-Band image sequences to obtain the lifetime and velocity distributions of MBPs. The influence of temporal/spatial sampling rates on these distributions is studied and used to correct the obtained lifetimes and velocity distributions for these digitalisation effects. After the correction of algorithm effects, we obtained a mean MBP lifetime of (2.50 +- 0.05) min and mean MBP velocities, depending on smoothing processes, in the range of (1 - 2) km/s. Corrected for temporal sampling effects, we obtained for the effective velocity distribution a Rayleigh function with a coefficient of (1.62 +- 0.05) km/s. The x- and y- components of the velocity distributions are Gaussians. The lifetime distribution can be fitted by an exponential function.