Abstract: In this paper, we consider the unsteady hydromagnetic incompressible viscous fluid flow through a porous medium in a horizontal channel under prescribed discharge, under the influence of inclined magnetic field. The undisturbed flow is due to a constant pressure gradient and the unsteadiness in the flow is created by imposing a time – dependent flux condition. The solutions for the ve...

Pulsed-current controlled wall motion in 20 m wide 200 m long 160 nm thick patterned Permalloy strips was studied using magnetic force microscopy. By sequential imaging, the displacement of Bloch walls as far as 200 m along the strip was observed. The direction of motion was in the same direction as the carrier velocity, which reversed with current polarity. The displacement per pulse was depen...

We discuss current observational and theoretical knowledge of magnetic fields, especially the large-scale structure in the disks and halos of spiral galaxies. Among other topics, we consider the enhancement of global magnetic fields in the interarm regions, magnetic spiral arms, and representations as superpositions of azimuthal modes, emphasizing a number of unresolved questions. It is argued ...