相关论文: Topological Constraints on Magnetic Relaxation

For any axisymmetric toroidal domain $\Omega \subset \mathbf{R}^3$ we prove that there is a locally generic set of divergence-free vector fields that are not topologically equivalent to any magnetohydrostatic (MHS) equilibrium in $\Omega$.…

Relaxed States of a slightly resistive and turbulent magnetized plasma is obtained by invoking the principle of minimum dissipation which leads to curl curl curl B = \lambda B . A solution of the above equation is accomplished using the…

The response of the solar coronal magnetic field to small-scale photospheric boundary motions including the possible formation of current sheets via the Parker scenario is one of open questions of solar physics. Here we address the problem…

3-D extended-MHD simulations of the magnetized ablative Rayleigh-Taylor instability are presented for the first time. Previous 2-D simulations claiming perturbation suppression by magnetic tension are shown to be misleading, as they do not…

The critical state problem in type-II superconductivity is described theoretically by a direct optimization method, which allows a straightforward treatment for non idealized geometries. Based on Faraday's law and the principle of minimum…

Magnetic helicity, and more broadly magnetic field line topology, impose constraints on the plasma dynamics. Helically interlocked magnetic rings are in a non-trivial topological state. It is harder to bring them into a topologically…

Stellar winds are thought to be the main process responsible for the spin down of main-sequence stars. The extraction of angular momentum by a magnetized wind has been studied for decades, leading to several formulations for the resulting…

A recent study [1] about the scaling with the aspect ratio (i.e. the ratio between the major and minor radius of the torus) of the dominant mode in Single Helical (SH) Reverse Field Pinch (RFP) plasmas has shown, at intermediate aspect…

The magnetic relaxation has been investigated in type II superconductors when the initial magnetic state is realized with entrapped and shielded flux (ESF) contemporarily. This flux state is produced by an inversion in the magnetic field…

Magnetic relaxation drives plasma toward lower-energy equilibria under helicity constraints. In ideal magnetohydrodynamics (MHD), helicity is locally conserved, while resistive theories such as Taylor relaxation preserve only global…

Ideal magnetohydrodynamics (IMHD) is strongly constrained by an infinite number of microscopic constraints expressing mass, entropy and magnetic flux conservation in each infinitesimal fluid element, the latter preventing magnetic…

Parker has hypothesised that, in a perfectly ideal environment, complex photospheric motions acting on a continuous magnetic field will result in the formation of tangential discontinuities corresponding to singular currents. We review…

Magnetic field topology frozen in ideal magnetohydrodynamics (MHD) and its breakage in near ideal MHD are reviewed in two parts. The first part gives a physically complete description of the frozen in field topology, taking magnetic flux…

We give theoretical analyses of the Magneto-Rayleigh-Taylor instability driven by a rotating magnetic field. Both slab and liner configurations with finite thicknesses are dealt with in the WKB and the non-WKB approximations. Results show…

We have investigated the relaxation of a hydrostatic hot plasma column containing toroidal magnetic field by the Current-Driven (CD) kink instability as a model of pulsar wind nebulae. In our simulations the CD kink instability is excited…

We numerically study the evolution of magnetic fields and fluid flows in a thin spherical shell. We take the initial field to be a latitudinally confined, predominantly toroidal flux tube. For purely toroidal, untwisted flux tubes, we…

We present results from 3D visco-resistive magnetohydrodynamic (MHD) simulations of the emergence of a convection zone magnetic flux tube into a solar atmosphere containing a pre-existing dipole coronal field, which is orientated to…

In turbulence, nonlinear terms drive energy transfer from large-scale eddies into small scales through the so-called energy cascade. Turbulence often relaxes toward states that minimize energy; typically these states are considered…

A new method to obtain the radial profile of the magnetic perturbation in a toroidal force-free plasma having circular cross section is developed. The method is quite general and can be applied to any circular low-beta plasma once suitable…

The topology of the coronal magnetic field produces a strong impact on the properties of the solar corona and presumably on the origin of the slow solar wind. To advance our understanding of this impact, we revisit the concept of so-called…