Summary: The Astrophysical Journal, 701:1911­1921, 2009 August 20 doi:10.1088/0004-637X/701/2/1911
C 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A.
CURRENT BUILDUP IN EMERGING SERPENTINE FLUX TUBES
E. Pariat1,3
, S. Masson2
, and G. Aulanier2
1 Space Weather Laboratory, NASA Goddard Space Flight Center Greenbelt, MD 20771, USA; epariat@helio.gsfc.nasa.gov
2 LESIA, Observatoire de Paris, CNRS, UPMC, Universit´e Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France
Received 2009 June 9; accepted 2009 July 6; published 2009 August 6
ABSTRACT
The increase of magnetic flux in the solar atmosphere during active-region formation involves the transport
of the magnetic field from the solar convection zone through the lowest layers of the solar atmosphere,
through which the plasma changes from > 1 to < 1 with altitude. The crossing of this magnetic transition
zone requires the magnetic field to adopt a serpentine shape also known as the sea-serpent topology. In the
frame of the resistive flux-emergence model, the rising of the magnetic flux is believed to be dynamically
driven by a succession of magnetic reconnections which are commonly observed in emerging flux regions as
Ellerman bombs. Using a data-driven, three-dimensional (3D) magnetohydrodynamic numerical simulation of
flux emergence occurring in active region 10191 on 2002 November 16­17, we study the development of 3D
electric current sheets. We show that these currents buildup along the 3D serpentine magnetic-field structure as
a result of photospheric diverging horizontal line-tied motions that emulate the observed photospheric evolution.

Source: Aulanier, Guillaume - Observatoire de Paris

Collections: Physics