Helical Kink Instability in the confined Solar Eruption on 2002 May 27

TL;DR

This study improves MHD modeling of a confined solar eruption, confirming that a kink-unstable flux rope with specific twist can explain observed eruption dynamics.

Contribution

It extends previous parametric studies by incorporating a more realistic flux rope initial condition aligned with observations, strengthening the kink instability model for confined eruptions.

Findings

Model closely matches observed eruption features.

Initial flux rope twist of about 4π is consistent with observations.

Supports kink instability as a key mechanism in confined eruptions.

Abstract

This paper presents an improved MHD modeling of the confined filament eruption in solar active region NOAA~9957 on 2002 May~27 by extending the parametric studies of the event in Torok & Kliem 2005 and Hassanin & Kliem 2016. Here the initial flux rope equilibrium is chosen to possess a small apex height identical to the observed initial filament height, which implies a more realistic inclusion of the photospheric line tying. The model matches the observations as closely as in the preceding studies, with the closest agreement again being obtained for an initial average flux rope twist of about $4\pi$. Thus, the model for strongly writhing confined solar eruptions, which assumes that a kink-unstable flux rope in the stability domain of the torus instability exists at the onset of the eruption's main acceleration phase, is further substantiated.