EDP Sciences
Free access
Volume 446, Number 1, January IV 2006
Page(s) 301 - 306
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20053445

A&A 446, 301-306 (2006)
DOI: 10.1051/0004-6361:20053445

A periodic arcade model for extended EUV filaments

U. Anzer1 and P. Heinzel2, 1

1  Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85740 Garching, Germany
    e-mail: ula@mpa-garching.mpg.de
2  Astronomical Institute, Academy of Sciences of the Czech Republic, 25165 Ondrejov, Czech Republic

(Received 17 May 2005 / Accepted 14 September 2005)

The extensions of H$\alpha$ filaments that are observed in EUV spectral lines require the presence of cool material in a large volume surrounding these filaments. This material can only be supported by magnetic fields with dips. Such dips can be generated by a sufficiently strong twisting of magnetic flux tubes. In the present paper we have extended earlier work to more realistic magnetic field configurations that are periodic in the x-direction. We derived approximate equilibria for twisted slender flux tubes and determined the region that contains dips. In addition we investigated the effects on our models of the mass loading due to a heavy prominence. Finally we compared our theoretical models with the EUV - observations. We conclude that these types of models are capable of explaining the basic features of the observations.

Key words: Sun: filaments -- Sun: magnetic fields -- Sun: UV radiation

© ESO 2006