Implications of rapid footpoint motions of photospheric flux tubes for coronal heating

Choudhuri, Arnab Rai and Auffret, Herve and Priest, Eric R (1993) Implications of rapid footpoint motions of photospheric flux tubes for coronal heating. In: Solar Physics, 143 (1). pp. 49-68.

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Abstract

Some recent observations at Pic-du-Midi (Mulleret al., 1992a) suggest that the photospheric footpoints of coronal magnetic field lines occasionally move rapidly with typical velocities of the order 3 km s–1 for about 3 or 4 min. We argue that such occasional rapid footpoint motions could have a profound impact on the heating of the quiet corona. Qualitative estimates indicate that these occasional rapid motions can account for the entire energy flux needed to heat the quiet corona. We therefore carry out a mathematical analysis to study in detail the response of a vertical thin flux tube to photospheric footpoint motions in terms of a superposition of linear kink modes for an isothermal atmosphere. We find the resulting total energy that is asymptotically injected into an isothermal atmosphere (i.e., an atmosphere without any back reflection). By using typical parameter values for fast and slow footpoint motions, we show that, even if the footpoints spend only 2.5% of the time undergoing rapid motions, still these rapid motions could be more efficient in transporting energy to the corona than the slow motions that take place most of the time.

Item Type:	Journal Article
Publication:	Solar Physics
Publisher:	Springer
Additional Information:	Copyright of this article belongs to Springer.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	10 Feb 2011 06:39
Last Modified:	10 Feb 2011 06:39
URI:	http://eprints.iisc.ac.in/id/eprint/35494

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