Accession Number : ADA187084
Title : Coronal Heating by Means of Helical Magnetohydrodynamic Turbulence.
Descriptive Note : Memorandum rept.,
Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC
Personal Author(s) : Dahlburg, R B ; Dahlburg, J P ; Mariska, J T
PDF Url : ADA187084
Report Date : 17 Dec 1987
Pagination or Media Count : 43
Abstract : Numerical simulations are used to investigate the relaxation of an unconfined, helically turbulent, fully three-dimensional magnetofluid, with conditions similar to those which are thought to result in the heating of the solar corona. In these simulations, the system evolves through a succession of force free states. After a relatively quiescent period of Ohmic decay, a phase of accelerated magnetic energy dissipation occurs. Some magnetic energy is transformed into kinetic energy, and the magnitude of entrophy created is a nontrival fraction of the mean square electric current. Concentrated vorticity structures are seen to play almost as important a role as electric current sheets in the heating process. Coincident with this accelerated dissipation process , a reorganization of the magnetic fields occurs, with transfer of magnetic energy to both shorter and longer wavelength modes than are initially present. The ratio of the magnetic field to the electric current density, alpha does not in general tend to assume a constant value in the force free regions during the evolution of the magnetofluid. Keywords: Coronal heating; Helical magnetohydrodynamic Turbulence; Direct numerical simulation.
Descriptors : *MAGNETOHYDRODYNAMICS, *SOLAR CORONA, ACCELERATED TESTING, CORONAS, CURRENT DENSITY, DISSIPATION, ELECTRIC CURRENT, ENERGY TRANSFER, HEATING, HELIXES, KINETIC ENERGY, MAGNETIC FIELDS, MATHEMATICAL MODELS, NUMERICAL ANALYSIS, RATIOS, SHEETS, STRUCTURES, TURBULENCE, VORTICES, DIGITAL SIMULATION, ROTATION, CORIOLIS EFFECT
Subject Categories : Plasma Physics and Magnetohydrodynamics
Distribution Statement : APPROVED FOR PUBLIC RELEASE