Statistical evolution of quiet-Sun small scale magnetic features using Sunrise observations

TL;DR

This study analyzes the evolution of small-scale magnetic features in the quiet Sun using high-resolution Sunrise observations, revealing detailed flux dynamics and introducing a new feature tracking algorithm.

Contribution

It presents a novel high-resolution analysis of quiet Sun magnetic features and a newly developed feature tracking algorithm, extending the flux detection limit significantly.

Findings

Unipolar appearance contributes more flux than emergence.

Bi-polar cancellation balances flux loss from disappearance.

Higher resolution allows tracking features with fluxes as low as 9×10^14 Mx.

Abstract

The evolution of small magnetic features in quiet regions of the Sun provides a unique window to probing solar magneto-convection. Here we analyze small scale magnetic features in the quiet Sun, using the high resolution, seeing-free observations from the Sunrise balloon borne solar observatory. Our aim is to understand the contribution of different physical processes, such as splitting, merging, emergence and cancellation of magnetic fields to the rearrangement, addition and removal of magnetic flux in the photosphere. We employ a statistical approach for the analysis and the evolution studies are carried out using a feature tracking technique. In this paper we provide a detailed description of the feature tracking algorithm that we have newly developed and we present the results of a statistical study of several physical quantities. The results on the fractions of the flux in the emergence, appearance, splitting, merging, disappearance and cancellation qualitatively agrees with other recent studies. To summarize, the total flux gained in unipolar appearance is an order of magnitude larger than the total flux gained in emergence. On the other hand, the bi-polar cancellation contributes nearly an equal amount to the loss of magnetic flux as unipolar disappearance. The total flux lost in cancellation is nearly $6-8$ times larger than the total flux gained in emergence. One big difference between our study and previous similar studies is that thanks to the higher spatial resolution of Sunrise we can track features with fluxes as low as $9\times10^{14}$ Mx. This flux is nearly an order of magnitude lower than the smallest fluxes of the features tracked in the highest resolution previous studies based on Hinode data.