Leaky magnetohydrodynamic waveguide model for the acceleration of high-speed solar wind streams in coronal holes

Journal Article · Mon Apr 01 04:00:00 EST 1985 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/163072· OSTI ID:5403642

Davila, J M

It is well established observationally that high-speed solar wind streams originate in coronal hole regions in the solor corona. Models of the solar wind flow based on this observation indicate that heat conduction alone cannot account for the observed properties of the wind and that other sources of heat and/or momentum must be sought. One suggested source for this additional momentum is ''wave pressure'' generated by magnetohydrodynamic (MHD) waves. Theories of wave-driven winds exist, but they are not consistent with the observed fact that high-speed streams originate in discrete magnetic structures in the solar corona. The waves assumed responsible for acceleration of the high-speed solar wind streams should have periods of approximately a hundred seconds if they are driven by photospheric turbulence. But MHD waves with periods this large have wavelengths lambda> or approx. =d, where d is the characteristic tranverse size of the coronal hole. Current theories for the acceleration of the solar wind by MHD waves are valid only if the wavelength of the disturbance is much smaller than the characteristic transverse size of the coronal structure. This limit is not appropriate for the propagation of disturbances with periods Proughly-equal100 s in the acceleration region of the solar wind. In this paper the effect of coronal hole magnetic structure on the propagation of MHD waves of all periods is considered. It is found that for the wave-period range discussed above the coronal hole structure acts as a ''leaky'' MHD waveguide, i.e., wave flux which enters at the base of the coronal hole is only weakly guided by the coronal hole structure. A significant amount of wave energy leaks through the side of the coronal hole into the surrounding corona.

• Research Organization: Laboratory for Astronomy and Solar Physics, NASA/Goddard Space Flight Center
• OSTI ID: 5403642
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 291:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
ANALYTICAL SOLUTION
ATMOSPHERES
DIFFERENTIAL EQUATIONS
DISPERSION RELATIONS
EIGENVALUES
EQUATIONS
FLUID FLOW
FLUID MECHANICS
HYDRODYNAMICS
HYDROMAGNETIC WAVES
MAGNETOHYDRODYNAMICS
MATHEMATICAL MODELS
MECHANICS
NUMERICAL SOLUTION
OSCILLATION MODES
OSCILLATIONS
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA ACCELERATION
SOLAR ACTIVITY
SOLAR CORONA
SOLAR WIND
STAR MODELS
STELLAR ATMOSPHERES
STELLAR CORONAE
WAVE EQUATIONS
WAVE PROPAGATION
WAVEGUIDES