-
Author(s):
Shao-ping Zhu, R. Horiuchi, T. Sato and The Complexity Simulation Group
-
Title:
Non-Taylor Magnetohydrodynamic Self-Organization
Date of publication:
Oct. 1994
-
Key words:
magnetohydrodynamic simulation, finite pressure, magnetic helicity, driven magnetic reconnection, stepwise relaxation, non-Taylor self-organization
-
Abstract:
A self-organization process in a plasma with a finite pressure is investigated by means of a three-dimensional magnetohydrodynamic simulation. It is demonstrated that a non-Taylor finite beta self-organized state is realized in which a perpendicular component of the electric current is generated and the force-free(parallel) current decreases until until they reach to almost the same level. The self-organized state is described by an MHD force-balance relation, namely, j perp = B x nabla p/B.B and J_ parallel = muB where mu is not a constant, and the pressure structure resembles the structure of the toroidal magnetic field intensity. Unless an anomalous perpendicular thermal conduction arises, the plasma cannot relax to a Taylor state but to a non-Taylor(non-force-free) self-organized state. This state becomes more prominent for a weaker resistivity condition. The non-Taylor state has a rather universal property, for example, independence of the initial beta value. Another remarkable finding is that the Taylor's conjecture of helicity conservation is, in a strict sense, not valid. The helicity dissipation occurs and its rate slows down critically in accordance with the stepwise relaxation of the magnetic energy. It is confirmed that the driven magnetic reconnection caused by the nonlinearly excited plasma kink flows plays the leading role in all of theses key features of the non-Taylor self-organization.
-
|
