It has been recognized long time ago that magnetohydrodynamic (MHD) waves must exist in the solar corona and their presence has a very important implication for the dynamics, heating and stability of the coronal plasma. A new era in the study of this solar region started after the launch of the high resolution SOHO and TRACE satellites which has changed our view of the solar corona in many ways. Using data provided by these space telescopes, scientists

The spatial structuring of solar and space plasmas is known to have a dispersive effect on waves. Many solar features possess a periodic structure with structures having alternating properties. Here the effect of periodic alternation of magnetic slabs on wave propagation is studied when the equilibrium has a steady motion (in line with observations). The dispersion relation for linear compressional waves is derived and analysed. The propagation of

In this paper we study the oscillations of a magnetic medium periodic in the x-direction with B parallel to z in the presence of a steady equilibrium field aligned flow. The case with no gravity and stepwise profile for B(x), allowing a normal mode analysis, is studied and the dispersion relation for linear compressional waves is derived. The propagation of waves is studied in particular case modelling the propagation of waves in the penumbral filamentary

The propagation of linear compressional waves is studied in magnetic flux tubes. The plasma inside and outside the tube is considered to be rarefied which confers an anisotropic character to the plasma. The anisotropy appears at different temperatures for parallel and perpendicular directions relative to the ambient magnetic field. The theoretical results are applied to study the effects of anisotropy and equilibrium steady flow on wave propagation

Recent high-resolution ground and space based telescopes have revealed that many solar features have substructures displaying a periodic or quasi-periodic pattern in transversal direction. In the present contribution we study the appearance of negative energy waves in a spatially periodic structure modelling the plume/interplume region above coronal holes. Negative energy waves (or instabilities) come into effect after a certain threshold for flow

In this work we present a possibility to realise the synchronization between two identical chaotic lasers by using an active control. We describe the action of the synchronization mechanism generally and then we apply it in the case of Lorenz-Robbins-Haken system. The numerical simulations of the analytical results are also presented.

An analogy between Lorenz-Robbins system for a convective fluid flow and Haken equations for a single mode laser is presented. The system called Lorenz-Robbins-Haken (LRH) is both analytical and numerical investigated. As the control parameter, which is proportional with the pump power, is varied, a rich behaviour of the system is observed, including the chaotic one. This behaviour corresponds to the experimental observations.