Forecasting Solar Wind Speeds

Abstract

By explicitly taking into account effects of Alfven waves, I derive from a simple energetics argument a fundamental relation which predicts solar wind (SW) speeds in the vicinity of the earth from physical properties on the sun. Kojima et al. recently found from their observations that a ratio of surface magnetic field strength to an expansion factor of open magnetic flux tubes is a good indicator of the SW speed. I show by using the derived relation that this nice correlation is an evidence of the Alfven wave which accelerates SW in expanding flux tubes. The observations further require that fluctuation amplitudes of magnetic field lines at the surface should be almost universal in different coronal holes, which needs to be tested by future observations.

5 pages, 2 figures embedded, ApJL, in press

References in corpus (2)

• Making the corona and the fast solar wind: a self-consistent simulation for the low-frequency Alfven waves from photosphere to 0.3AU
• On the Heating of the Solar Corona and the Acceleration of the Low-Speed Solar Wind by Acoustic Waves Generated in Corona

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• Extended MHD modeling of the steady solar corona and the solar wind
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• The origin of slow Alfvénic solar wind at solar minimum
• Parametric decay and the origin of the low frequency Alfvénic spectrum of the solar wind
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• Stellar Winds and Coronae of Low-mass Pop. II/III Stars
• Turbulence-Driven Coronal Heating and Improvements to Empirical Forecasting of the Solar Wind
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• Stellar Magnetic Fields as a Heating Source for Extrasolar Giant Planets
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• The Spectroscopic Footprint of the Fast Solar Wind
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• The winds of young Solar-type stars in the Hyades
• Recent Observations of Plasma and Alfvenic Wave Energy Injection at the Base of the Fast Solar Wind
• Self-consistent Simulations of Alfven Wave Driven Winds from the Sun and Stars
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• Thermal Response of A Solar-like Atmosphere to An Electron Beam from A Hot Jupiter: A Numerical Experiment
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• Astrophysics in 2006
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• Magnetic Configurations Related to the Coronal Heating and Solar Wind Generation I. Twist and Expansion Profiles of Magnetic Loops Produced by Flux Emergence
• Threaded-Field-Lines Model for the Low Solar Corona Powered by the Alfven Wave Turbulence
• On Competing Models of Coronal Heating and Solar Wind Acceleration: The Debate in '08
• Proposal of a Novel Physical Parameter Characterizing Solar Wind Speed in a Wave-Driven Model
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