Saddle-center and periodic orbit: Dynamics near symmetric heteroclinic connection.

An analytic reversible Hamiltonian system with two degrees of freedom is studied in a neighborhood of its symmetric heteroclinic connection made up of a symmetric saddle-center, a symmetric orientable saddle periodic orbit lying in the same level of a Hamiltonian, and two non-symmetric heteroclinic orbits permuted by the involution. This is a codimension one structure; therefore, it can be met generally in one-parameter families of reversible Hamiltonian systems. There exist two possible types of such connections depending on how the involution acts near the equilibrium. We prove a series of theorems that show a chaotic behavior of the system and those in its unfoldings, in particular, the existence of countable sets of transverse homoclinic orbits to the saddle periodic orbit in the critical level, transverse heteroclinic connections involving a pair of saddle periodic orbits, families of elliptic periodic orbits, homoclinic tangencies, families of homoclinic orbits to saddle-centers in the unfolding, etc. As a by-product, we get a criterion of the existence of homoclinic orbits to a saddle-center.

Solitary wave solutions of nonlocal sine-Gordon equations.

In this paper a nonlocal generalization of the sine-Gordon equation, u(tt)+sin u=( partial differential / partial differential x) integral (- infinity ) (+ infinity )G(x-x('))u(x(') )(x('),t)dx(') is considered. We present a brief review of the applications of such equations and show that involving such a nonlocality can change features of the model. In particular, some solutions of the sine-Gordon model (for example, traveling 2pi-kink solutions) may disappear in the nonlocal model; furthermore, some new classes of solutions such as traveling topological solitons with topological charge greater than 1 may arise. We show that the lack of Lorenz invariancy of the equation under consideration can lead to a phenomenon of discretization of kink velocities. We discussed this phenomenon in detail for the special class of kernels G(xi)= summation operator (j=1) (N)kappa(j)e(-eta(j)mid R:ximid R:), eta(j)>0, j=1,2, em leader,N. We show that, generally speaking, in this case the velocities of kinks (i) are determined unambiguously by a type of kink and value(s) of kernel parameter(s); (ii) are isolated i.e., if c(*) is the velocity of a kink then there are no other kink solutions of the same type with velocity c in (c(*)- varepsilon,c(*)+ varepsilon ) for a certain value of varepsilon. We also used this special class of kernels to construct approximations for analytical and numerical study of the problem in a more general case. Finally, we set forth results of the numerical investigation of the problem with the kernel that is the McDonald function G(xi) approximately K(0)(mid R:ximid R:/lambda) (lambda is a parameter) that have applications in the Josephson junction theory. (c) 1998 American Institute of Physics.

On small stationary localized solutions for the generalized 1-D Swift-Hohenberg equation.

We prove the existence of small localized stationary solutions for the generalized Swift-Hohenberg equation and find under some assumption a part of a boundary of their existence in the parameter plane. The related stationary equation creates a reversible Hamiltonian system with two degrees of freedom that undergoes the Hamiltonian-Hopf bifurcation with an additional degeneracy. We investigate this bifurcation in a two-parameter unfolding by means of the sixth-order normal form for the related Hamiltonian. The region where no localized solutions exist has been pointed out as well. (c) 1995 American Institute of Physics.

Homoclinical structures in nonautonomous systems: Nonautonomous chaos.

For general nonautonomous systems, integral sets similar to homoclinic structures of an autonomous system are introduced. A description of integral curves near such a set is given.

Complex dynamics and bifurcations in a Hamiltonian system having a transversal homoclinic orbit to a saddle focus.

A Hamiltonian system having a saddle-focus singular point with a transversal homoclinic orbit is considered. The bifurcations that occur upon a variation of the Hamiltonian are studied. Reconstructions of a symbolic system describing the hyperbolic set are investigated. Bifurcations linked with the appearance of Smale horseshoes are pointed out. The results are applied to a system determining traveling-wave solutions of the Landau-Lifshitz equation. Multisolitons with any number of humps can exist.

Nonintegrable field equations and homoclinic loops of Hamiltonian systems.

Connections between soliton or self-localized states of nonlinear wave equations and special objects (homo- and heteroclinic trajectories) of dynamical systems are considered.