相关论文: Hall cascade with fractional magnetic helicity in …

We consider the evolution of magnetic fields under the influence of Hall drift and Ohmic decay. The governing equation is solved numerically, in a spherical shell with r_i/r_o = 0.75. Starting with simple free decay modes as initial…

The Hosking integral, which characterizes magnetic helicity fluctuations in subvolumes, is known to govern the decay of magnetically dominated turbulence. Here we show that, when the evolution of the magnetic field is controlled by the…

The dynamics of magnetic field decay with Hall drift is investigated. Assuming that axisymmetric magnetic fields are located in a spherical crust with uniform conductivity and electron number density, long-term evolution is calculated up to…

Helical magnetohydrodynamic turbulence with Hall effects is ubiquitous in heliophysics and plasma physics, such as star formation and solar activities, and its intrinsic mechanisms are still not clearly explained. Direct numerical…

We consider the effect of Hall-drift on the evolution of magnetic fields in neutorn star crusts using a finite difference code. Previously, most studies have focused on the situation where the ohmic term dominates the evolution. Here, we…

We present calculations of magnetic field evolution by the Hall effect and Ohmic decay in neutron star crusts. We first discuss when and for which neutron stars the Hall effect is important relative to Ohmic decay. We compute the evolution…

The braking torque that dictates the timing properties of magnetars is closely tied to the large-scale dipolar magnetic field on their surface. The formation of this field has been a topic of ongoing debate. One proposed mechanism, based on…

The Hall effect is an important nonlinear mechanism affecting the evolution of magnetic fields in neutron stars. Studies of the governing equation, both theoretical and numerical, have shown that the Hall effect proceeds in a turbulent…

Powerful lasers may in future produce magnetic fields that would allow us to study turbulent magnetohydrodynamic inverse cascade behavior. This has so far only been seen in numerical simulations. In the laboratory, however, the produced…

We have carried out numerical simulations of freely decaying magnetohydrodynamic (MHD) turbulence in three dimensions, which can be applied to the evolution of stochastic magnetic fields in the early Universe. For helical magnetic fields an…

We perform direct numerical simulations of three-dimensional freely decaying magnetohydrodynamic (MHD) turbulence. For helical magnetic fields an inverse cascade effect is observed in which power is transfered from smaller scales to larger…

We study the non--linear evolution of magnetic fields in neutron star crusts with special attention to the influence of the Hall drift. Our goal is to understand the conditions for fast dissipation due to the Hall term in the induction…

In our conventional understanding, large-scale magnetic fields are thought to originate from an inverse cascade in the presence of magnetic helicity, differential rotation, or a magneto-rotational instability. However, as recent simulations…

In the presence of magnetic helicity, inverse transfer from small to large scales is well known in magnetohydrodynamic (MHD) turbulence and has applications in astrophysics, cosmology, and fusion plasmas. Using high resolution direct…

In the presence of a strong magnetic field and under conditions as realized in the crust and the superfluid core of neutron stars the Hall--drift dominates the field evolution. We show by a linear analysis that for a sufficiently strong…

There exists both theoretical and observational evidence that the magnetic field decay in neutron stars may proceed in a pronounced non--linear way during a certain episode of the neutron star's life. In the presence of a strong magnetic…

We propose a mechanism for the fast dissipation of magnetic fields which is effective in a stratified medium where ion motions can be neglected. In such a medium, the field is frozen into the electrons and Hall currents prevail. Although…

In former papers we showed that during the decay of a neutron star's magnetic field under the influence of the Hall--drift, an unstable rise of small--scale field structures at the expense of the large--scale background field may happen.…

We investigate the stability of the Hall-MHD system and determine its importance for neutron stars at their birth, when they still consist of differentially rotating plasma permeated by extremely strong magnetic fields. We solve the…

We show that oppositely directed fluxes of energy and magnetic helicity coexist in the inertial range in fully developed magnetohydrodynamic (MHD) turbulence with small-scale sources of magnetic helicity. Using a helical shell model of MHD…