A model for FMR above the second order SUHL instability is introduced. Because of the nonlocal character of the demagnetization field novel spatial patterns occur in the weakly and strongly nonlinear regime. The spatial state of a ferromagnetic sample for pump Now, for g O, -3b4 -b3. The first pitchfork bifurcation at Rc is subcritical; (D) b4 < 0, b3 < 4 4 . Similar to case A except that no second bifurcation occurs. There exists an interval1 [kc Ak, kc + Ak] with Ak cc (R Rc)112 of spatially periodic solutions which are Eckhaus-stable [6]. Figure 2 shows the occurrence of these cases for different values of the _resonance detuning Aw,,, = wres w and the demagnetization factor NL. Fig. 2. Occurrence of bifurcation scenarios A-D of figure 1 for equation (1) in the parameter space defined by the resonance detuning Aw, and the demagnatization factor NL . g = 0.01, w = 1, and a is arbitrary. The hatched area is defined by the absence of the second order SUHL instability. The strongly nonlinear case: for large L we typically get stationary state which are built up from two or more of different locally stable . An example with two uniform phases is shown in figure 3. The understanding of such a behaviour of the nonlocal dynamics is in principle very simple: consider the evolution equation (1) with the spatially averaged magnetization fi as a freely adjustable control parameter. Next, we evaluate all values of fi where (1) has at least two stable stationary solutions m l and m2. Then we compute fi in a self-consistent manner: f i = q f i l ( f i ) + ( l q ) m 2 ( m ) , with 0 I q 1 1, (6) where q is that portion of the total state which is in the phase rnl . This consideration is correct as long as the sum over the widths of all domains walls are much smaller than L. Fig. 3. A stationary state of equation (1) after a computer simulation with 500 mesh points, g = 0.05, w = 1, NL = 113, Awres = 0, 0 = 0.04 = 2.6& and L = 100. a is indirectly determined through kc = 100 (2zlL). The angles of the two phase mi = cos 4; sin eie, + sin 4; sin diel, + cos &e,, (i = 1,2) , are 41 = -124.4g0, O1 = 8-24' and e2 = -1.340, e2 = 52.880.