Thermal Instability of a Couple-Stress Ferromagnetic Fluid in the Presence of Variable Gravity Field and Horizontal Magnetic Field with Hall Currents Saturating in a Porous Medium


Sudhir Kumar Pundir, Pulkit Kumar Nadian, Rimple Pundir
Department of  Mathematics S.D. (P.G.) College, Muzaffarnagar, U.P, India.


The thermal instability of a couple-stress ferromagnetic fluid in the presence of variable gravity field and horizontal magnetic field with hall currents is considered, which saturates in a porous medium. We have used a linear stability theory and normal mode technique to discover the precise solution for a layer of couple-stress ferromagnetic fluid contained between two free boundaries. A dispersion relation governing the effect of medium permeability, couple-stress, magnetic field and hall current is derived. For the case of stationary convection, we have found that these parameters have both stabilizing and destabilizing effect under certain conditions. From the present study, we have got additionally determined that magnetization has a stabilizing effect on the system. Graphs in each case have been plotted by giving numerical values to these parameters. In the absence of magnetic field (hence hall current), the principle of exchange of stabilities is found to hold true under certain conditions.