virial theorem is important for understanding stellar structures. it produces an interesting connection between magnetic and gravitational energies. using the general form of the virial theorem including the magnetic field (toroidal magnetic field), we may explain the solar dynamo model in relation to variations of the magnetic and gravitational energies. we emphasize the role of the gravitatio...

Variations in polarization e ciency (p=A) of interstellar grains as a function of environment place vital constraints on models for the mechanism of their alignment. We use polarimetry of background eld stars to investigate alignment in the Taurus dark cloud as a function of optical depth for extinctions of AK < 2:5 (AV < 25). Results show a strong systematic trend in polarization e ciency with...

If the galaxy is born with a very weak seed eld, magnetic energy starts growing rapidly on scales smaller than the smallest turbulent eddies in the interstellar medium (ISM). The small scale eld acts like a tangled network of rubber bands, making the ISM elastic to large scale motions. The hydrodynamic shear modes of the interstellar turbulence, which start out with zero frequency, become Alfve...

The collimation of an isotropic, non-magnetic protostellar wind by an ordered magnetic eld in the ambient medium is investigated using self-consistent magnetohydrodynamic simulations in two-dimensions. The strong protostellar wind in ates a low density bubble in the ambient medium. The growth of this bubble is con ned along the direction of the ambient magnetic eld when the gas pressure in the ...

Systematic variations with wavelength in the position angle of interstellar linear polarization of starlight may be indicative of multiple cloud structure along the line of sight. We use polarimetric observations of two stars (HD 29647, HD 283809) in the general direction of TMC{1 in the Taurus Dark Cloud to investigate grain properties and cloud structure in this region. We show the data to be...

Virial theorem is important for understanding stellar structures. It produces an interesting connection between magnetic and gravitational energies. Using the general form of the virial theorem including the magnetic field (toroidal magnetic field), we may explain the solar dynamo model in relation to variations of the magnetic and gravitational energies. We emphasize the role of the gravitatio...

alfvén waves dissipation is an extensively studied mechanism for the coronal heating problem. these waves can be generated by magnetic reconnection and propagated along the reconnected field lines. here, we study the generation of alfvén waves at the presence of both steady flow and sheared magnetic field in the longitudinally density stratified of solar spicules. the initial flow is assumed to...

Considering the magneto-hydrodynamic equations in a non-relativistic multi uid framework, we study the behavior of small amplitude perturbations in cold quark matter. Magneto-hydrodynamic equations, along with a suitable equation of state for the cold quark matter, are expanded using the reductive perturbation method. It is shown that in small amplitude approximation, such a medium should be co...

An irrigation scheduling model (ISM) consisting of a database management system (DBMS), model base and graphical user interface (GUI) was developed for performing irrigation scheduling under various management options for both single and multiple ®elds. The ISM is based on a daily water balance approach and uses climatological, crop and soil data as input. Depending on the availability of clima...

cosmic rays (cr) travel at speeds essentially indistinguishable from the speed of light. however whilst travelling through magnetic fields, both regular and turbulent, they are delayed behind the light since they are usually charged particles and their paths are not linear. those delays can be so long that they are an impediment to correctly identifying sources which may be variable in time. fu...