Evolution of Filament Barbs

TL;DR

This paper investigates rapid changes in filament barb chirality, linking these to small-scale magnetic flux emergence and cancellation at the filament channel border, based on detailed case analysis.

Contribution

It provides detailed observational evidence connecting filament barb chirality changes to flux emergence and cancellation at the filament channel.

Findings

Barb chirality can change within hours.

Flux emergence and cancellation influence barb evolution.

One barb overlay a small polarity inversion line.

Abstract

We present a selected few cases in which the sense of chirality of filament barbs changed within as short as hours. We investigate in detail a quiescent filament on 2003 September 10 and 11. Of its four barbs displaying such changes only one overlay a small polarity inversion line inside the EUV filament channel (EFC). No magnetic elements with magnitude above the noise level were detected at the endpoints of all barbs. In particular, a pair of barbs first approached toward and then departed from each other in H-alpha, with the barb endpoints migrating as far as ~10". We conclude that the evolution of the barbs was driven by flux emergence and cancellation of small bipolar units at the EFC border.