Large scale reconstruction of the solar coronal magnetic field

Tangled Magnetic Fields in Astro- and Plasma Physics; Quantised Flux in Tightly Knotted and Linked Systems

Amari, T.^1 ; Aly, J.-J.^2 ; Chopin, P.^1 ; Canou, A.^1 ; Mikic, Z.^3

CNRS, Centre de Physique Théorique de l'Ecole Polytechnique, Palaiseau cedex

F-91128, France^1

AIM-Unité Mixte de Recherche, CEA-CNRS-Université Paris VII-UMR n 7158, Centre d'Études de Saclay, Gif sur Yvette cedex

F-91191, France^2

Predictive Science Inc., San Diego

CA

92121, United States^3

关键词: Cartesian geometry;    Coronal magnetic fields;    Eruptive events;    Large scale structures;    Multiple connections;    Nonlinear force;    On-board spacecrafts;    Spherical geometries;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/544/1/012012/pdf
DOI  :  10.1088/1742-6596/544/1/012012

来源: IOP

【 摘 要 】

It is now becoming necessary to access the global magnetic structure of the solar low corona at a large scale in order to understand its physics and more particularly the conditions of energization of the magnetic fields and the multiple connections between distant active regions (ARs) which may trigger eruptive events in an almost coordinated way. Various vector magnetographs, either on board spacecraft or ground-based, currently allow to obtain vector synoptic maps, composite magnetograms made of multiple interactive ARs, and full disk magnetograms. We present a method recently developed for reconstructing the global solar coronal magnetic field as a nonlinear force-free magnetic field in spherical geometry, generalizing our previous results in Cartesian geometry. This method is implemented in the new code XTRAPOLS, which thus appears as an extension of our active region scale code XTRAPOL. We apply our method by performing a reconstruction at a specific time for which we dispose of a set of composite data constituted of a vector magnetogram provided by SDO/HMI, embedded in a larger full disk vector magnetogram provided by the same instrument, finally embedded in a synoptic map provided by SOLIS. It turns out to be possible to access the large scale structure of the corona and its energetic contents, and also the AR scale, at which we recover the presence of a twisted flux rope in equilibrium.