Magnetic balltracking: Tracking the photospheric magnetic flux

TL;DR

This paper introduces 'magnetic balltracking', a new high-precision algorithm for tracking small-scale magnetic features in the solar photosphere, enabling detailed analysis of flux evolution and magnetic activity.

Contribution

The work presents a novel magnetic balltracking technique that accurately tracks magnetic features and quantifies flux changes from magnetograms, improving upon previous methods.

Findings

Successfully tracked magnetic flux emergence events.

Quantified flux ranges associated with X-ray loop brightenings.

Demonstrated the method's capability with real solar data.

Abstract

Context: One aspect of understanding the dynamics of the quiet Sun is to quantify the evolution of the flux within small-scale magnetic features. These features are routinely observed in the quiet photosphere and were given various names, such as pores, knots, magnetic patches. Aims: This work presents a new algorithm for tracking the evolution of the broad variety of small-scale magnetic features in the photosphere, with a precision equal to the instrumental resolution. Methods: We have developed a new technique to track the evolution of the individual magnetic features from magnetograms, called "magnetic balltracking". It quantifies the flux of the tracked features, and it can track the footpoints of magnetic field lines inferred from magnetic field extrapolation. The algorithm can detect and quantify flux emergence, as well as flux cancellation. Results: The capabilities of magnetic balltracking are demonstrated with the detection and the tracking of two cases of magnetic flux emergence that lead to the brightening of X-ray loops. The maximum emerged flux ranges from 10^{18} Mx to 10^{19} Mx (unsigned flux) when the X-ray loops are observed.