Purpose The purpose of this paper is used to study the combined effect of solute gradient and magnetic field on dusty couple-stress fluid in the presence of rotation through a porous medium. Design/methodology/approach The perturbation technique (experimental method) is applied in this study. Findings For the case of stationary convection, solute gradient and rotation have stabilizing effect, whereas destabilizing effect is found in dust particles in the system. Couple stress and medium permeability both have dual character to its stabilizing effect in the absence of magnetic field and rotation. Magnetic field succeeded in establishing a stabilizing effect in the absence of rotation. Originality/value The results are discussed by allowing one variable to vary and keeping other variables constant, as well as by drawing graphs.

Purpose This study aims to focus on the effect of hall currents on the thermal stability of a couple-stress fluid with a uniform horizontal magnetic field. Design/methodology/approach The thermal perturbation method is used for the analytical solution. The analysis is administered within the framework of linear stability theory and normal mode technique on the convection for a fluid layer contained between two boundaries for which an exact solution is obtained. Findings For the case of stationary convection, a dispersion relation governing the effect of hall currents magnetic field and couple stress are derived. Results from the current study concluded that magnetic field has stabilizing effect whereas hall currents are found to have a destabilizing effect on the system. Couple stress, however, has a dual character in contrast to its stabilizing effect in the absence of hall currents. The Oscillatory modes are introduced due to the presence of a magnetic field in the system. Graphs are plotted by giving numerical values to the parameters to depict the stability characteristics in each case. Originality/value This research paper is new and original.