Emergence of non-twisted magnetic fields in the Sun: Jets and atmospheric response

TL;DR

This study uses 3D MHD simulations to explore how the length of a buoyant, non-twisted magnetic flux tube affects its emergence and dynamic behavior in the solar atmosphere, revealing differences in emergence speed, instability, and jet formation.

Contribution

It provides new insights into how the length of the buoyant part of a flux tube influences magnetic emergence and jet dynamics in the solar atmosphere.

Findings

Larger {} leads to faster emergence and more expansion.

Both cases form magnetic bipoles that interact and produce jets.

Plasmoid ejections and impulsive heating occur at the current layer.

Abstract

Aims. We study the emergence of a non-twisted flux tube from the solar interior into the solar atmosphere. We investigate whether the length of the buoyant part of the flux tube (i.e. {\lambda}) affects the emergence of the field and the dynamics of the evolving magnetic flux system. Methods. We perform three-dimensional (3D), time-dependent, resistive, compressible MHD simulations using the Lare3D code. Results. We find that there are considerable differences in the dynamics of the emergence of a magnetic flux tube when {\lambda} is varied. In the solar interior, for larger values of {\lambda}, the rising magnetic field emerges faster and expands more due to its lower magnetic tension. As a result, its field strength decreases and its emergence above the photosphere occurs later than in the smaller {\lambda} case. However, in both cases, the emerging field at the photosphere becomes unstable in two places, forming two magnetic bipoles that interact dynamically during the evolution of the system. Most of the dynamic phenomena occur at the current layer, which is formed at the interface between the interacting bipoles. We find the formation and ejection of plasmoids, the onset of successive jets from the interface, and the impulsive heating of the plasma in the solar atmosphere. We discuss the triggering mechanism of the jets and the atmospheric response to the emergence of magnetic flux in the two cases.