Dynamical magnetic reconnection in Parker's coronal heating model
Autor: | G. Van Hoven, D. L. Hendrix |
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Rok vydání: | 1997 |
Předmět: |
Physics
Atmospheric Science Magnetic energy Aerospace Engineering Astronomy and Astrophysics Magnetic reconnection Mechanics Coronal loop Corona Magnetic flux Nanoflares Geophysics Classical mechanics Space and Planetary Science Physics::Space Physics Astrophysics::Solar and Stellar Astrophysics General Earth and Planetary Sciences Magnetic pressure Joule heating |
Zdroj: | Advances in Space Research. 19:1865-1869 |
ISSN: | 0273-1177 |
DOI: | 10.1016/s0273-1177(97)00089-6 |
Popis: | The excitation (flares, ejections, heating, …) of the corona can be understood in terms of the dynamics of the confectively driven magnetized plasma. In particular, anomalous ohmic heating may be a consequence of the formation and rapid dissipation of small-scale magnetic fields in the corona. We have performed numerical simulations of the loop heating model proposed by Parker (1972, 1994), and have studied its dynamics and global power balance in order to assess its viability as a coronal heating candidate, with promising results. Our results suggest the following view of the small-scale dynamics of coronal loops. First of all, photospheric granular motions quasi-statically twist the magnetic field of the corona in a random-walk fashion. In topologically closed structures, the perpendicular magnetic energy increases, causing magnetic shear to build up at the quasi-separatrices of the resulting close-packed magnetic flux tubes. At some point, the boundary driving causes this stressed configuration to cross the threshold of an ideal time-scale MHD instability (possibly magnetic coalescence or resistive tearing) or a point of nonequilibrium and the field lines pinch toward a small-scale sheared configuration. It then becomes energetically favorable for dynamic reconnection to occur, producing narrow current sheets and an Ohmic heating rate sufficient to balance the input Poynting flux. |
Databáze: | OpenAIRE |
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