A study of the effect of an externally imposed magnetic field on the axisymmetry-breaking instability of an axisymmetric convective flow, associated with crystal growth from bulk of melt, is presented. Convection in a vertical cylinder with a parabolic temperature profile on the sidewall is considered as a representative model. A parametric study of the dependence of the critical Grashof number...

We present a theoretical formalism for calculating the anisotropy and polarization of photon emission due to a spiralling beam of electrons colliding with an ensemble of atoms or ions. For an axisymmetric beam with a given velocity angular distribution, the polarization and angular distribution of the resulting radiation can be characterized by the expansion coefficients of the distribution fun...

Increasing observations are becoming available about a relatively weak, but persistent, non-axisymmetric magnetic field co-existing with the dominant axisymmetric field on the Sun. It indicates that the non-axisymmetric magnetic field plays an important role in the origin of solar activity. A linear non-axisymmetric α − Ω dynamo model is set up to discuss the characteristics of the axisymmetric...

The principles of Ultrasonic Computed Tomography (UCT) are reviewed in this paper. The UCT is a powerful nondestructive technique in medicine and recently in industry to reveal an image of a slice of an object or body. The advantage of UCT over other conventional techniques in imaging is that a computed tomogram yields quantitative information about the section of interest. Experimental works o...

Plumes due to localized buoyancy sources are of wide interest owing to their prevalence in many situations. This study investigates the transition from laminar to turbulent dynamics. Several experiments have reported that this transition is sensitive to external perturbations. As such, a well-controlled set-up has been chosen for our numerical study, consisting of a localized heat source at the...

We here describe a new synthetic catalogue generator , based on a statistical model of the Galaxy, and use it to model the spatial and kinematic distribution of a subset of the Hipparcos Catalogue, speciically OB stars in the plane of the Galaxy. To accurately model this stellar population a method is developed which does not make the usual assumption of uniformity across the eld. This populati...

Using a transient mathematical heat transfer model including heat conduction, radiation, and radio frequency (RF) induction heating, we numerically investigate the time evolution of temperature gradients in axisymmetric growth apparatus during sublimation growth of silicon carbide (SiC) bulk single crystals by physical vapor transport (PVT) (modified Lely method). Temperature gradients on the g...