Two-frequency parametric excitation of the surface of viscous magnetic fluid

The parametric instability of the surface of viscous magnetic fluid has been discussed in the presence of two frequency (n(1)omega, n(2)omega) oscillating magnetic field H-0(t) = H-0[1 + m[cos(chi)cos(n(1)omegat) + sin(chi)cos(n(2)omegat + phi]]. The marginal stability curves have been drawn and they divide the (k,m) plane into unstable and stable zones. Here k is the wave number and m is the amplitude of excitation. Also discussed is the stability of the interface of two magnetic fluids. We have studied the same two systems under gravity modulation also. (C) 2002 Elsevier Science B.V. All rights reserved.