EDP Sciences
Free access
Volume 434, Number 3, May II 2005
Page(s) 1155 - 1163
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20041268

A&A 434, 1155-1163 (2005)
DOI: 10.1051/0004-6361:20041268

A solar active region loop compared with a 2D MHD model

C. Gontikakis1, G. J. D. Petrie2, H. C. Dara1 and K. Tsinganos2

1  Research Center of Astronomy and Applied Mathematics, Academy of Athens, Soranou Efessiou 4, 115 27, Athens, Greece
    e-mail: [cgontik;edara]@cc.uoa.gr
2  IASA and Section of Astrophysics, Astronomy and Mechanics, Department of Physics, University of Athens, Panepistimiopolis, 157 84, Athens, Greece
    e-mail: gpetrie@hao.ucar.edu;tsingan@phys.uoa.gr

(Received 10 May 2004 / Accepted 5 January 2005 )

We analyzed a coronal loop observed with the Normal Incidence Spectrometer (NIS), which is part of the Coronal Diagnostic Spectrometer (CDS) on board the Solar and Heliospheric Observatory (SOHO). The measured Doppler shifts and proper motions along the selected loop strongly indicate unidirectional flows. Analysing the Emission Measure Curves of the observed spectral lines, we estimated that the temperature along the loop was about 380 000 K. We adapted a solution of the ideal MHD steady equations to our set of measurements. The derived energy balance along the loop, as well as the advantages/disadvantages of this MHD model for understanding the characteristics of solar coronal loops are discussed.

Key words: Sun: corona -- Sun: magnetic fields -- magnetohydrodynamics (MHD) -- Sun: UV radiation

© ESO 2005