Related papers: Magnetic Helicity and Large Scale Magnetic Fields:…
Magnetic fields appear to be present in essentially all astrophysical environments, including galaxies, clusters of galaxies and voids. There are both observational and theoretical motives for considering the possibility of their origin…
Stability and reconnection of magnetic fields play a fundamental role in natural and man-made plasma. In these applications the field's topology determines the stability of the magnetic field. Here I will describe the importance of one…
We review our current understanding of galactic dynamo theory, paying particular attention to numerical simulations both of the mean-field equations and the original three-dimensional equations relevant to describing the magnetic field…
Turbulence is believed to play important roles in the origin of cosmic magnetism. While it is well known that turbulence can efficiently amplify a uniform or spatially homogeneous seed magnetic field, it is not clear whether or not we can…
It is argued that large scale cosmic magnetic field could be generated in the primeval plasma slightly before hydrogen recombination. Non-zero vorticity, necessary for that, might be created by the photon diffusion in the second order in…
Celestial objects, from earth like planets to clusters of galaxies, possess angular momentum and magnetic fields. Here we compare the rotational and magnetic energies of a whole range of these celestial objects together with their…
A non-linear, time-dependent, magnetically driven dynamo theory which shows how magnetically dominated configurations can relax to become helical on the largest scale available is presented. Coupled time-dependent differential equations for…
An overview is given of the helicity of the velocity field (``kinetic'' helicity to distinguish it from the ``magnetic'' helicity used in magnetohydrodynamics, astrophysics, and solar physics; or simply \emph{helicity} in this Chapter) and…
It is demonstrated that the two-point correlation function of the magnetic helicity in the case of zero mean magnetic field has anomalous scalings for both, compressible and incompressible turbulent helical fluid flow. The magnetic helicity…
Helical magnetic background fields with adjustable pitch angle are imposed on a conducting fluid in a differentially rotating cylindrical container. The small-scale kinetic and current helicities are calculated for various field geometries,…
Blackman & Brandenburg argued that magnetic helicity conservation in dynamo theory can in principle be captured by diagrams of mean field dynamos when the magnetic fields are represented by ribbons or tubes, but not by lines. Here we…
Magnetic fields play a vital role in numerous astrophysical processes such as star formation and the interstellar medium. In particular, their role in the formation and evolution of galaxies is not well understood. This paper presents…
Models for astrophysical plasmas often have magnetic field lines that leave the boundary rather than closing within the computational domain. Thus, the relative magnetic helicity is frequently used in place of the usual magnetic helicity,…
The behavior of spinning particles in the stationary homogeneous magnetic field is considered and all types of trajectories for massive and massless particles are found. It is shown that spin of particles in a magnetic field is always…
A thermodynamic model for the generation of magnetic fields in the planets is proposed, considering crossed effects between gravitational and electric forces. The magnetic field of the Earth is estimated and found to be in agreement with…
Observations of Faraday rotation and synchrotron emission in galaxy clusters imply large-scale magnetic fields with $\mu\mathrm{G}$ strengths possibly extending back to $z=4$. Non-radiative cosmological simulations of galaxy clusters show a…
The origin and growth of magnetic fields in galaxies is still something of an enigma. It is generally assumed that seed fields are amplified over time through the dynamo effect, but there are few constraints on the timescale. It has…
Blazar observations point toward the possible presence of magnetic fields over intergalactic scales of the order of up to $\sim1\,$Mpc, with strengths of at least $\sim10^{-16}\,$G. Understanding the origin of these large-scale magnetic…
The electromagnetic helicity of the free electromagnetic field and the static magnetic helicity are shown to be two different embodiments of the same physical quantity, the total helicity. The total helicity is the sum of two terms: a term…
The origin of astrophysical magnetic fields observed in galaxies and clusters of galaxies is still unclear. One possibility is that primordial magnetic fields generated in the early Universe provide seeds that grow through compression and…