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Title: The emergence of weakly twisted magnetic fields in the sun

We have studied the emergence of a weakly twisted magnetic flux tube from the upper convection zone into the solar atmosphere. It is found that the rising magnetized plasma does not undergo the classical, single Ω-shaped loop emergence, but it becomes unstable in two places, forming two magnetic lobes that are anchored in small-scale bipolar structures at the photosphere, between the two main flux concentrations. The two magnetic lobes rise and expand into the corona, forming an overall undulating magnetic flux system. The dynamical interaction of the lobes results in the triggering of high-speed and hot jets and the formation of successive cool and hot loops that coexist in the emerging flux region. Although the initial emerging field is weakly twisted, a highly twisted magnetic flux rope is formed at the low atmosphere, due to shearing and reconnection. The new flux rope (hereafter post-emergence flux rope) does not erupt. It remains confined by the overlying field. Although there is no ejective eruption of the post-emergence rope, it is found that a considerable amount of axial and azimuthal flux is transferred into the solar atmosphere during the emergence of the magnetic field.
Authors:
 [1] ;  [2] ;  [3]
  1. Section of Astrophysics, Astronomy and Mechanics, Department of Physics, University of Athens, Panepistimiopolis 15784, Athens (Greece)
  2. School of Mathematics and Statistics, St. Andrews University, St. Andrews KY169SS (United Kingdom)
  3. National Observatory of Athens, Lofos Nymphon, Thissio 11810, Athens (Greece)
Publication Date:
OSTI Identifier:
22342006
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 778; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; CONCENTRATION RATIO; CONVECTION; ECOLOGICAL CONCENTRATION; ERUPTION; INTERACTIONS; MAGNETIC FIELDS; MAGNETIC FLUX; PHOTOSPHERE; PLASMA; RISE; SUN; VELOCITY