Double-diffusive convection with an imposed magnetic field (Q1078018)

The stability of the double-diffusive magnetoconvection subject to infinitesimal and finite amplitude disturbances is studied in this paper. It is reported that the marginal stability of oscillatory modes occurs on a hyperboloid in space determined by R, \(R_ s\), and \(Q\tau_ 2\) where R and \(R_ s\) are the thermal and solute Rayleigh numbers, Q a magnetic number and \(\tau_ 2\) is the ratio of magnetic to thermal diffusivities. The effect of the magnetic field is to make the system more stable, as expected, and the region of salt-finger and overstable modes decreases as \(\tau_ 1\) increases, where \(\tau_ 1\) is the ratio of the solute and thermal diffusivities. It is found that the salt-finger and over-stable modes may be simultaneously unstable over a wide range of conditions and the effect of the magnetic field is to suppress this region.