The Influence of the Electrical Conductivity of the Boundary on the Stability of a Hydromagnetic - Rotating Fluid Layer

The stability of a horizontal layer of Boussinesq fluid, heated from below and cooled from above, rotating uniformly about the vertical in the presence of a uniform vertical magnetic field is studied for the case where the thermal diffusivity K is much larger than the magnetic diffusivity n (= l/μlδe where μ is the magnetic permeability and μ, is the electrical conductivity). The stability problem depends on the five dimensionless numbers Ra, T, M, q, qb. The Rayleigh number, Ra, is a measure of the buoyancy force, the Taylor number, T, is a measure of the Coriolis force, the Hartmann number, M, is a measure of the Lorentz force and q=k/n, while qb=Kμδb, where ub is the electrical conductivity of the boundary.