ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The nonlinear mechanism responsible for the spin wave envelope soliton formation in magnetic films from input pulses of finite duration is the four-wave process with conservation law ω(k0)+ω(k0)=ω(k0+κ)+ω(k0−κ), κ(very-much-less-than)k0. This process is also responsible for modulation instability of CW wave in a nonlinear dispersive medium and can only take place if the nonlinearity N and the dispersion D in the medium have opposite signs. In a dissipative medium this process has a finite amplitude threshold determined by the dissipation parameter γ and the effective "detuning'' Δω proportional to the dispersion D and the square of the modulation wave number κ, ||cursive-phi||th2=[γ2+(Δω)2/4]/||NΔω||, hereafter referred to as Eq. (1), where ||cursive-phi|| is the dimensionless wave amplitude. For the process of modulational instability of a CW wave Δω=Dκ2. For the process of soliton formation from a finite input pulse (of the duration T) Δω=Dκ2n, where κn=(2n−1)π/vT, n is the number of solitons formed, and v is the group velocity of spin waves. Equation (1) gives a good description of the recent measurements of thresholds of spin wave envelope soliton formation in YIG films presented in Ref. . In particular, describes correctly the shape of the threshold curve, positions of threshold minima for the formation of one and two solitons, and explains the finite intercept on the threshold power dependence on the inverse square of the input pulse duration that was not explained in Ref. . © 1996 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.361327
Permalink
