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Observations and Models of Coronal Heating

Published online by Cambridge University Press:  13 May 2016

F. Malara
Affiliation:
Dipartimento di Fisica, Università della Calabria, via P. Bucci, 87036 Rende (CS), Italy Istituto Nazionale per la Fisica della Materia, Unità di Cosenza, via P. Bucci, 87036 Rende (CS), Italy
M. Velli
Affiliation:
Dipartimento di Astronomia e Scienza dello Spazio, Università di Firenze, largo E. Fermi, Firenze, Italy Istituto Nazionale per la Fisica della Materia, Unità di Pisa, Pz Torricelli 2, 56100 Pisa, Italy

Abstract

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Energy release in the solar Corona is characterized by a sequence of space and time localized events, whose intensity follows power-law distributions. In quiet Sun regions, small energy events, possibly under the detection threshold, dominate, thus supporting the “nanoflare” scenario of coronal heating. Two complementar models of heating are discussed, in connection with the above observational features. The first model is based on Alfvénic wavepackets dissipation in 3D force-free magnetic fields; the presence of regions of chaoticity of magnetic lines allows for a fast wave dissipation, within a fraction of a solar radius. The second model describes a MHD turbulence in low-β plasma, in which magnetic energy is continuously furnished by slow photospheric motions. Energy release events corresponds dissipation of current sheets, often associated with magnetic reconnection. The resulting distribution of dissipated power follows a power law, similar to observations.

Type
Session V: Coronal Heating and Solar Wind Acceleration
Copyright
Copyright © Astronomical Society of the Pacific 2001 

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