| In this thesis, the influence of higher-order effects on microwave magnetic-envelope solitons in ferromagnetic films is investigated analytically and numerically based on the nonlineax Schré°€inger equation. For this purpose, first the derivation of the perturbed nonlinear Schrodinger equation with the consideration of the third-order dispersion and forth-order nonlinear effect by the author is given, followed by the adiabatic solutions of this equation by using the perturbation methods in bright and dark soliton case, respectively. Next, we numerically modeled this equation in bright soliton case. Our treatment shows the third-order dispersion with coefficient /33 > 0 (/33 <0) has the influence on bright solitons, leading to phase decreasing (increasing), positive (nega- tive) shift of the soliton centre, amplitude decreasing (increasing), pulse width increasing (decreasing), and growing tail (growing tail and oscillations in forward position of the pulse). Besides, the rise and fall of amplitude, the increase and decrease of pulse width both exhibit periodicity. Forth-order nonlinear effect has the influence on increasing the phase. When third-order dispersion and the forth-order nonlinear effect are considered simuitaneously, third-order dispersion dominates the influence and forth-order nonlinear effect only has a contribution to the phase. In dark soliton case, the third-order dispersion with coefficient /33 > 0 (/33 <0) has the influence on them, leading to red shift (blue shift) of spectrum, amplitude increas- ing (decreasing), pulse width decreasing (increasing), and phase increasing (decreasing). Forth-order nonlinear effect has the influence on a positive shift of the soliton centre. When third-order dispersion and the forth-order nonlinear effect are considered simui- taneously, third-order dispersion dominates the influence and forth-order nonlinear effect only has a contribution to a positive shift of the soliton centre.
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