The weakly nonlinear regime of a viscoelastic Navier–Stokes fluid is investigated. For the purely hydrodynamic case, it is known that large-scale perturbations tend to the minima of a Ginzburg-Landau free-energy functional with a double-well (fourth-order) potential. The dynamics of the relaxation process is ruled by a one-dimensional Cahn– Hilliard equation that dictates the hyperbolic tangent...

We study dynamical consequences of the kink instability of a twisted coronal flux rope, using the force-free coronal loop model by Titov & Démoulin (1999) as the initial condition in ideal-MHD simulations. When a critical value of the twist is exceeded, the long-wavelength (m=1) kink mode develops. Analogous to the well-known cylindrical approximation, a helical current sheet is then formed at ...

Plasma blobs are observed to be weak density enhancements as radially-stretched structures emerging from the cusps of quiescent coronal streamers. In this paper, it is suggested that the formation of blobs is a consequence of an intrinsic instability of coronal streamers occurring at a very localized region around the cusp. The evolutionary process of the instability, as revealed in our calcula...

We construct and study two kink theories. One contains a static 2-kink configuration with controllable binding energy. The other locally stable non-topological solution, which we call lavion. new models are 1D analogs of non-integrable systems in higher dimensions such as the Skyrme model realistic vortex systems. To help theories, derive simple expression for interaction energy between kinks.

In the field of nonlinear optics, quantum mechanics, condensed matter physics, and wave propagation in rigid other instability phenomena, Schrödinger equation has significant applications. this study, soliton solutions space-time fractional cubic with Kerr law nonlinearity are investigated using an extended direct algebraic method. The found form hyperbolic, trigonometric, rational functions. A...

This paper seeks to find optical soliton solutions for Lakshmanan–Porsezian–Daniel (LPD) model with the parabolic law of nonlinearity. The spatiotemporal dispersion is included model, as it can contribute handling problem internet bottleneck. study was performed analytically using traveling wave hypothesis reduce an integrable form. Then, resulting equation handled two approaches, namely, auxil...