Magnetic dynamo action in two-dimensional turbulent magneto-hydrodynamics

Technical Report · Tue Jun 01 04:00:00 EDT 1976

OSTI ID:7215165

Fyfe, D; Joyce, G; Montgomery, D

Two-dimensional magnetohydrodynamic turbulence is explored by means of numerical simulation. Previous analytical theory, based on non-dissipative constants of the motion in a truncated Fourier representation, is verified by following the evolution of highly non-equilibrium initial conditions numerically. Dynamo action (conversion of a significant fraction of turbulent kinetic energy into long-wavelength magnetic field energy) is observed. It is conjectured that, in the presence of dissipation and external forcing, a dual cascade will be observed for zero-helicity situations. Energy will cascade to higher wave numbers simultaneously with a cascade of mean square vector potential to lower wave numbers, and this cascading will lead to an omni-directional magnetic energy spectrum which varies as 1/k 3 at lower wave numbers, simultaneously with a buildup of magnetic excitation at the lowest wave number of the system. Equipartition of kinetic and magnetic energies is expected at the highest wave numbers in the system. (auth)

• Research Organization: Iowa Univ., Iowa City (USA). Dept. of Physics and Astronomy
• OSTI ID: 7215165
• Report Number(s): N-76-27004; NASA-CR-148291
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EARTH ATMOSPHERE
FARADAY INDUCTION
FLUID MECHANICS
FOURIER TRANSFORMATION
HYDRODYNAMICS
INDUCTION
INTEGRAL TRANSFORMATIONS
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MAGNETOSPHERE
MECHANICS
SIMULATION
TRANSFORMATIONS
TURBULENCE
TWO-DIMENSIONAL CALCULATIONS