How flux feeding causes eruptions of solar magnetic flux ropes with the hyperbolic flux tube configuration?

TL;DR

This study uses a 2.5D MHD model to investigate how flux feeding influences the eruption of solar magnetic flux ropes with hyperbolic flux tube configurations, revealing that flux feeding can both trigger and stabilize eruptions depending on flux injection.

Contribution

It demonstrates that flux feeding can induce eruptions in HFT-configured flux ropes by injecting axial flux, expanding understanding of eruption mechanisms beyond previous bald patch models.

Findings

Flux feeding injects axial magnetic flux into the flux rope.

Flux feeding can trigger eruptions if enough axial flux is injected.

Flux feeding can stabilize flux ropes if the injected flux is insufficient.

Abstract

Coronal magnetic flux ropes are generally considered to be the core structure of large-scale solar eruptions. Recent observations found that solar eruptions could be initiated by a sequence of "flux feeding," during which chromospheric fibrils rise upward from below, and merge with a pre-existing prominence. Further theoretical study has confirmed that the flux feeding mechanism is efficient in causing the eruption of flux ropes that are wrapped by bald patch separatrix surfaces. But it is unclear how flux feeding influences coronal flux ropes that are wrapped by hyperbolic flux tubes (HFT), and whether it is able to cause the flux-rope eruption. In this paper, we use a 2.5-dimensional magnetohydrodynamic model to simulate the flux feeding processes in HFT configurations. It is found that flux feeding injects axial magnetic flux into the flux rope, whereas the poloidal flux of the rope is reduced after flux feeding. Flux feeding is able to cause the flux rope to erupt, provided that the injected axial flux is large enough so that the critical axial flux of the rope is reached. Otherwise, the flux rope system evolves to a stable equilibrium state after flux feeding, which might be even farther away from the onset of the eruption, indicating that flux feeding could stabilize the rope system with the HFT configuration in this circumstance.