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Astron. Astrophys. 329, 1111-1118 (1998)

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Coronal plasmoid dynamics

I. Dissipative MHD approach

C. Delannée 1, S. Koutchmy 1, I.S. Veselovsky 2 and A.N. Zhukov 2

1 CNRS, Institut d'Astrophysique de Paris, 98 bis, Boulevard Arago, F-75014 Paris, France
2 Institute of Nuclear Physics, Moscow State University, 119899 Moscow, Russia

Received 8 July 1996 / Accepted 5 August 1997


Energy and momentum balance equations of the dissipative MHD approach are applied to the coronal plasmoid phenomenon observed with the Canada-France-Hawaii Telescope during the July 11, 1991 total solar eclipse. The situation is marginal for the applicability of the MHD description,which has been used for orders of magnitude estimates of the governing physical parameters. Their analysis confirms the suggestion about the possibility for a relatively cold but rapidly moving plasma body to heat the corona through dissipative viscous effects. It also shows that magnetic stresses, gas pressure gradients and viscous drags by the fast plasma flows from the chromosphere are viable candidates to lift the plasmoid against the gravity force.

Key words: Sun: corona – Sun: magnetic fields – MHD

© European Southern Observatory (ESO) 1998

Online publication: December 16, 1997