Photospheric signatures of CME onset

TL;DR

This study provides observational evidence linking topological magnetic changes at the photosphere, especially near polarity inversion lines, to the onset of coronal mass ejections, enhancing understanding of CME initiation mechanisms.

Contribution

It demonstrates that magnetic winding flux signatures at the photosphere are associated with CME onset, offering a new method to identify CME source regions within active regions.

Findings

Winding flux signatures correlate with CME onset times and locations.

Photospheric topological changes are a common feature of CME initiation.

The method enables locating CME sources within active regions.

Abstract

Coronal mass ejections (CMEs) are solar eruptions that involve large-scale changes to the magnetic topology of an active region. There exists a range of models for CME onset which are based on twisted or sheared magnetic field above a polarity inversion line (PIL). We present observational evidence that topological changes at PILs, in the photosphere, form a key part of CME onset, as implied by many models. In particular, we study the onset of 30 CMEs and investigate topological changes in the photosphere by calculating the magnetic winding flux, using the \texttt{ARTop} code. By matching the times and locations of winding signatures with CME observations produced by the \texttt{ALMANAC} code, we confirm that these signatures are indeed associated with CMEs. Therefore, as well as presenting evidence that changes in magnetic topology at the photosphere are a common signature of CME onset, our approach also allows for the finding of the source location of a CME within an active region.