Experiments on the instability of a layer of mercury heated from below and subject to the simultaneous action of a magnetic field and rotation. II

Abstract

Experiments are described which are devoted to the determination of the sizes of the convection cells which appear at marginal stability in a layer of mercury heated from below and subject to the action of a magnetic field either alone or in the presence of rotation. The experiments confirm the theoretical predictions of Chandrasekhar regarding the wave number of the disturbance which is manifested at marginal stability. In particular, under the simultaneous action of magnetic fields and rotation, the present experiments fully confirm the predicted discontinuous change in the wave number at the point where, for increasing field strength (for given rotation), the transition from cellular convection to overstable convection takes place.