An Efficient Approximation of the Coronal Heating Rate for Use in Global Sun-Heliosphere Simulations

Abstract

The origins of the hot solar corona and the supersonically expanding solar wind are still the subject of debate. A key obstacle in the way of producing realistic simulations of the Sun-heliosphere system is the lack of a physically motivated way of specifying the coronal heating rate. Recent one-dimensional models have been found to reproduce many observed features of the solar wind by assuming the energy comes from Alfven waves that are partially reflected, then dissipated by magnetohydrodynamic turbulence. However, the nonlocal physics of wave reflection has made it difficult to apply these processes to more sophisticated (three-dimensional) models. This paper presents a set of robust approximations to the solutions of the linear Alfven wave reflection equations. A key ingredient to the turbulent heating rate is the ratio of inward to outward wave power, and the approximations developed here allow this to be written explicitly in terms of local plasma properties at any given location. The coronal heating also depends on the frequency spectrum of Alfven waves in the open-field corona, which has not yet been measured directly. A model-based assumption is used here for the spectrum, but the results of future measurements can be incorporated easily. The resulting expression for the coronal heating rate is self-contained, computationally efficient, and applicable directly to global models of the corona and heliosphere. This paper tests and validates the approximations by comparing the results to exact solutions of the wave transport equations in several cases relevant to the fast and slow solar wind.

13 pages (emulateapj style), 7 figures, ApJ, in press. A brief FORTRAN subroutine that computes the coronal heating rate will be distributed with this paper as "online-only material," and this material is also available at http://www.cfa.harvard.edu/~scranmer/Data/NonWKB/

References in corpus (9)

• Self-consistent Coronal Heating and Solar Wind Acceleration from Anisotropic Magnetohydrodynamic Turbulence
• Coronal Holes
• Time-Distance Seismology of the Solar Corona with CoMP
• Empirical Constraints on Proton and Electron Heating in the Fast Solar Wind
• Alfven Wave Reflection and Turbulent Heating in the Solar Wind from 1 Solar Radius to 1 AU: an Analytical Treatment
• Coronal Heating, Weak MHD Turbulence and Scaling Laws
• Turbulence in the sub-Alfvénic solar wind driven by reflection of low-frequency Alfvén waves
• The Turbulent Heating Rate in Strong MHD Turbulence with Nonzero Cross Helicity
• Effects of non-WKB Alfven waves on a multicomponent solar wind with differential ion flow

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