Temporal evolution of magnetic elements

TL;DR

This study investigates the dynamic evolution of weak magnetic fields in the quiet Sun, revealing small-scale flux cancellation events and their chromospheric effects through high-resolution spectro-polarimetric observations.

Contribution

It provides observational evidence of magnetic flux cancellation in the quiet Sun and links photospheric magnetic changes to chromospheric emission variations.

Findings

Magnetic flux cancellation occurs in small-scale opposite-polarity patches.

Cancelled magnetic flux leaves minor traces at chromospheric levels.

Small-scale magnetic features can disappear within minutes.

Abstract

We study the structure and evolution of the magnetic field of the quiet Sun by investigating weak spectro-polarimetric signals. To this end, we observed a quiet region close to the disk center with the German VTT in Tenerife, July 07, 2006. We recorded 38 scans of the same area. Each scan was eight arcsec wide and observed within about 100 seconds. We used POLIS to simultaneously observe Stokes profiles of the neutral iron lines at 630.15 and 630.25 nm, the Stokes-I profile of the Ca II H line at 396.8 nm, and a continuum speckle channel at 500 nm. We witness two examples of magnetic flux cancellation of small-scale opposite-polarity patches, followed by an enhanced chromospheric emission. In each case, the two opposite-polarity patches gradually became smaller and, within a few minutes, the smaller one completely disappeared. The larger patch also diminished significantly. We provide evidence for a cancellation scenario in the photosphere which leaves minor traces at the chromospheric level.