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Heating of coronal holes by the resonant absorption and dissipation of Alfven waves and its relation to solar wind accelerationCoronal hole regions are well known sources of high-speed solar wind, however to account for the observed properties of the solar wind a source of momentum and heat must be included. Alfven waves were suggested as the possible source of heating that accelerates the solar wind. We investigate the propagation of the Alfven waves in coronal holes via numerical solution of the linearized 2-D resistive MHD equations in slab geometry. The Alfven waves are driven at the lower boundary of the coronal hole and propagate into the corona. The waves are reflected at the coronal hole boundary and part of the wave energy leaks out of the coronal hole. We compare the calculated wavelengths and the attenuation rate of the fast mode Alfven waves in the leaky waveguide formed by the coronal hole with the analytical ideal MHD solutions. The formation of resonance heating layers is found to occur when shear Alfven waves propagate in an inhomogeneous coronal hole. The heating is enhanced when fast mode waves couple to the shear Alfven waves. The narrow heating layers are formed near the location of the ideal resonance, which might occur near the coronal hole boundary for a nearly constant density coronal hole, surrounded by a higher density plasma. We investigate the dependence of the heating on the driver frequency, the Lundquist number, and on the heliocentric distance. and find that the low frequency Alfven waves can be an efficient source of heating at large distances from the Sun. We discuss the relation of our results to the observed properties of high-speed solar wind and coronal holes.
Document ID
19960021370
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Ofman, L.
(Hughes STX, Inc. Greenbelt, MD United States)
Davila, J. M.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
August 17, 2013
Publication Date
June 30, 1995
Subject Category
Solar Physics
Accession Number
96N24766
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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