We perform cosmological, hydrodynamic simulations of magnetic elds in galaxy clusters. The computational code combines the special-purpose hardware Grape for calculating gravitational interaction, and smooth-particle hydrodynamics for the gas component. We employ the usual MHD equations for the evolution of the magnetic eld in an ideally conducting plasma. As a rst application, we focus on the ...

The number of pulsars with detected emission at X-ray and γ-ray energies has been steadily growing, showing that beams of high-energy particles are commonly accelerated in pulsar magnetospheres, even though the location and number of acceleration sites remain unsettled. Acceleration near the magnetic poles, close to the polar cap surface or to higher altitudes in the slot gap along the last ope...

Recent palaeomagnetic studies suggest that excursions of the geomagnetic ¢eld, during which the intensity drops suddenly by a factor of 5^10 and the local direction changes dramatically, are more common than previously expected. The `normal' state of the geomagnetic ¢eld, dominated by an axial dipole, seems to be interrupted every 30^100 kyr; it may not therefore be as stable as we thought. We ...

We report results of a three dimensional, high resolution (up to 512) numerical investigation of supersonic compressible magnetohydrodynamic turbulence. We consider both forced and decaying turbulence. The model parameters are appropriate to conditions found in Galactic molecular clouds. We find that the dissipation time of turbulence is of order the flow crossing time or smaller, even in the p...

Trajectories of charged particle in combined poloidal, toroidal magnetic eld and rotation-induced unipolar electric eld superposed in Schwarzschild background geometry have been investigated extensively in the context of accreting black holes. The main purpose of the paper is to obtain a reasonably well insight on the e ect of spacetime curvature to the electromagnetic eld surrounding black hol...

The large time asymptotics of a magnetic eld in a turbulent-correlated (in time) ow of an ideal incompressible uid are studied. It is shown that the magnetic eld exhibits the dynamo eeect (exponential stretching) unless the Lagrangian ow generated by the velocity eld is (almost surely) distance preserving; and it is intermittent unless the Lagrangian ow associated to the turbulent component of ...

The large time asymptotics of a magnetic eld in a turbulent -correlated (in time) ow of an ideal incompressible uid are studied. It is shown that the magnetic eld exhibits the dynamo e ect (exponential stretching) unless the Lagrangian ow generated by the velocity eld is (almost surely) distance preserving; and it is intermittent unless the Lagrangian ow associated to the turbulent component of...

There are two existing avenues to interpreting the diffuse ISM: the theorist’s approach in which real data is interpreted numerically in the context of simulations, and the observer’s approach in which objects are found and categorized by eye. We are pioneering a middle way, following the fast-growing science of machine vision to extract shape information from complex maps of the diffuse Galact...

Magnetic eld enters the corona from the interior of the Sun through isolated magnetic features on the solar surface. These features correspond to the tops of submerged magnetic ux tubes, and coronal eld lines often connect one ux tube to another, deening a pattern of inter-linkage. Using a model eld, in which ux tubes are represented as point magnetic charges, it is possible to quantify this in...

This paper 1 reviews the contrasting properties of radio and EUV/X{ray observations for the study of the solar atmosphere. The emphasis is placed on explaining the nature of radio observations to an EUV/X{ray audience. Radio emission is produced by mechanisms which are well-understood within classical physics. Bremsstrahlung tends to be dominant at low frequencies, while gyroresonance emission ...