NONLINEAR MODULATION OF TRAVELING ROLLS IN MAGNETOCONVECTION

Modulational dynamics of oscillatory travelling rolls in magnetoconvec tion is studied near the onset of a Hopf bifurcation. Using weakly non linear analysis, we derive an envelope equation of oscillatory travell ing rolls in the plane perpendicular to an ambient vertical magnetic f ield. The envelope equation is the Davey-Stewartson (DS) equation with complex coefficients, from which we obtain criteria for the modulatio nal (Benjamin-Feir) instability of oscillatory travelling rolls.