THE EMERGENCE OF A TWISTED FLUX TUBE INTO THE SOLAR ATMOSPHERE: SUNSPOT ROTATIONS AND THE FORMATION OF A CORONAL FLUX ROPE

By Yuhong Fan. 2009

148 citations recorded by the source corpus.

We present a three-dimensional simulation of the dynamic emergence of a twisted magnetic flux tube from the top layer of the solar convection zone into the solar atmosphere and corona. It is found that after a brief initial stage of flux emergence during which the two polarities of the bipolar region become separated and the tubes intersecting the photosphere become vertical, significant rotational motion sets in within each polarity. The rotational motions of the two polarities are found to twist up the inner field lines of the emerged fields such that they change their orientation into an inverse configuration (i.e., pointing from the negative polarity to the positive polarity over the neutral line). As a result, a flux rope with sigmoid-shaped, dipped core fields forms in the corona, and the center of the flux rope rises in the corona with increasing velocity as the twisting of the flux rope footpoints continues. The rotational motion in the two polarities is a result of propagation of nonlinear torsional Alfvén waves along the flux tube, which transports significant twist from the tube's interior portion toward its expanded coronal portion. This is a basic process whereby twisted flux ropes are developed in the corona with increasing twist and magnetic energy, leading up to solar eruptions.

Subfields: Astronomy and Astrophysics, Computational Mechanics

View Paper: https://www.semanticscholar.org/paper/158447edd24bb6b8ffc02a311958bec7439a7f8d

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Computational Mechanics

Citations in the corpus

Physics of Solar Prominences: II—Magnetic Structure and Dynamics (2010, background): “A flux rope may form through the reconnection of emerged sheared field lines that lie above the emerging tubes axis (Manchester et al., 2004; Magara, 2006; Archontis and Török, 2008; Fan, 2009).”
The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs – Space-Weather HMI Active Region Patches (2014, methodology): “171 For the CEA version, the native three-component vector magnetic-field output from the 172 inversion – expressed as field strength [B], inclination [γ], and azimuth [ψ] in the image plane – 173 is transformed to the components Br, Bθ, and Bφ in standard heliographic spherical coordinates 174 [êr,”