Driving convection in a fluid layer by a temperature gradient or a heat current.

Bifurcation properties, stability behavior, dynamics, and the heat transfer of convection in a horizontal fluid layer that is driven away from thermal equilibrium by imposing a vertical temperature difference are compared with those resulting from imposing a heat current. Similarities and differences are elucidated. In particular various paradigmatic backwards bifurcating convection structures that occur, e.g., in binary fluid mixtures are determined numerically for the two different driving mechanisms. Conditions are given under which current driven convection is stable when temperature driven convection is unstable.