Anisotropies in magnetic field evolution and local Lyapunov exponents

Tang, X.Z. ; Boozer, A.H.

Princeton University. Plasma Physics Laboratory.

关键词: Lyapunov Method;    Magnetic Fields;    70 Plasma Physics And Fusion Technology;    Coordinates;    Lagrangian Function;   

DOI  :  10.2172/750157
RP-ID  :  PPPL--3417
RP-ID  :  AC02-76CH03073
RP-ID  :  750157

美国|英语

来源: UNT Digital Library

【 摘 要 】

The natural occurrence of small scale structures and the extreme anisotropy in the evolution of a magnetic field embedded in a conducting flow is interpreted in terms of the properties of the local Lyapunov exponents along the various local characteristic (un)stable directions for the Lagrangian flow trajectories. The local Lyapunov exponents and the characteristic directions are functions of Lagrangian coordinates and time, which are completely determined once the flow field is specified. The characteristic directions that are associated with the spatial anisotropy of the problem, are prescribed in both Lagrangian and Eulerian frames. Coordinate transformation techniques are employed to relate the spatial distributions of the magnetic field, the induced current density, and the Lorentz force, which are usually followed in Eulerian frame, to those of the local Lyapunov exponents, which are naturally defined in Lagrangian coordinates.