This report is a presentation of the theoretical aspects of the investigations and a few confirmatory laboratory studies of the dispersion process. The basic assumptions associated with the development of the dispersion equation, based on the applicability of a heuristic expression similar to Pick's law, are described. In general, these assumptions limit its application to a homogeneous medium ...

We study theoretically the propagation of electromagnetic waves in an infinite and homogenous medium with both temporal and spatial dispersion included. We derive a partial differential equation connecting temporal and spatial dispersion to achieve negative group velocity. Exact solutions of the equation are found and shown to lead to the possibility of exciting constant negative group velocity...

[1] We thank Lim [2005] for providing this opportunity to clarify the restrictions and confirm the applicability of the results of LaBolle et al. [2000]. LaBolle et al. [2000] develop generalized stochastic differential equations (SDE) that converge to advection dispersion equations with discontinuous dispersion tensor D. The problem of interest here relates to equation (15a) of LaBolle et al. ...

A mathematical method called subordination broadens the applicability of the classical advection--dispersion equation for contaminant transport. In this method, the time variable is randomized to represent the operational time experienced by different particles. In a highly heterogeneous aquifer, the operational time captures the fractal properties of the medium. This leads to a simple, parsimo...

The diffusive-viscous wave equation plays an important role in seismic exploration and it can be used to explain the frequency-dependent reflections observed both in laboratory and field data. The numerical solution to this type of wave equation is needed in practical applications because it is difficult to obtain the analytical solution in complex media. Finite-difference method (FDM) is the m...

We study stability of N-soliton solutions of the FPU lattice equation. Solitary wave solutions of FPU cannot be characterized as a critical point of conservation laws due to the lack of infinitesimal invariance in the spatial variable. In place of standard variational arguments for Hamiltonian systems, we use an exponential stability property of the linearized FPU equation in a weighted space w...

The dispersion coefficient tensor including off-diagonal components was introduced in the flow with secondary currents, which is called skewed shear flow dispersion SSFD coefficient tensor, in this paper. To observe the detailed effect of cross-dispersion terms in SSFD model on solute dispersion, mathematical analysis of eigenvalue problem with respect to the equation with SSFD coefficient tens...

We consider the weakly dissipative and weakly dispersive Burgers-Hopf-Korteweg-de-Vries equation with the diffusion coefficient ε and the dispersion rate δ in the range δ/ε → 0. We study the travelling wave connecting u(−∞) = 1 to u(+∞) = 0 and show that it converges strongly to the entropic shock profile as ε, δ → 0. Key-words Travelling waves, moderate dispersion, Korteweg de Vries equation, ...

The modulation instability of the one-dimensional cubic-quintic complex Ginzburg-Landau equation with fouth-order dispersion and gain terms, a. k. a., the quintic complex Swift-Hohenberg equation, is investgated. The effects of the fourth-order terms to the modulational instability is studied. We numerically investigate the dynamics of the modulational instability in the presence of the fourtho...

We describe the breathing dynamics of the self-similar core and the oscillating tails of a dispersion-managed (DM) soliton. The path-averaged propagation equation governing the shape of the DM soliton in an arbitrary dispersion map is derived. The developed theory correctly predicts the locations of the dips in the tails of the DM soliton. A general solution of the propagation equation is prese...