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| Titel |
Coronal heating and wind acceleration by nonlinear Alfvén waves – global simulations with gravity, radiation, and conduction |
| VerfasserIn |
T. K. Suzuki |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 15, no. 2 ; Nr. 15, no. 2 (2008-03-26), S.295-304 |
| Datensatznummer |
250012617
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| Publikation (Nr.) |
 copernicus.org/npg-15-295-2008.pdf |
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| Zusammenfassung |
| We review our recent results of global one-dimensional (1-D) MHD simulations
for the acceleration of solar and stellar winds.
We impose transverse photospheric motions corresponding to the granulations,
which generate outgoing Alfvén waves.
We treat the propagation and dissipation of the Alfvén waves and consequent
heating from the photosphere by dynamical simulations in a self-consistent
manner.
Nonlinear dissipation of Alfven waves becomes quite effective
owing to the stratification of the atmosphere (the outward decrease of
the density).
We show that the coronal heating and the solar wind acceleration in the
open magnetic field regions are natural consequence of the footpoint
fluctuations of the magnetic fields at the surface (photosphere).
We find that the properties of the solar wind sensitively depend on
the fluctuation amplitudes at the solar surface because of the nonlinearity
of the Alfvén waves, and that the wind speed at 1 AU is mainly controlled by
the field strength and geometry of flux tubes.
Based on these results, we point out that both fast and slow solar winds
can be explained by the dissipation of nonlinear Alfvén waves in a unified
manner.
We also discuss winds from red giant stars driven by Alfvén waves, focusing
on different aspects from the solar wind. |
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