Approximate analytical solutions of the waves and fields inside and outside the coupling region for an arbitrary number of propagating modes of all kinds and an arbitrary number of couplings and mode conversions are presented. The method is applied to the propagation of electromagnetic fields in a plane- stratified cold plasma as an illustrative example.
Field variables in a slowly varying plasma are solutions of a system of differential and integral equations. To solve these equations, the fields are expanded in the eigenvectors of an algebraic plasma tensor, and the plasma equations can be transformed into a system of transport equations. The expansion becomes singular when eigenvalues coincide (for example in the case of mode conversion). It is shown how this problem can be resolved for an arbitrary system of Maxwell and/or fluid equations in arbitrary dimensions and for every kind of medium. The method is applied to horizontal stratified media as a simple example.
Most of the mode conversion theories considered so far assume only a plane-layered medium, i.e. a medium where the parameters depend on one spatial coordinate. We generalize the mode-conversion method of Cairns and Lashmore-Davies to plasmas with two-dimensional inhomogeneities. In the method presented here, the frequencies ω 1 and ω 2 of the uncoupled modes belonging to two different dispersion equations are considered as functions of the space variable r and the wave vector k and are coupled together via a small quantity η. We calculate the energy transmission and conversion coefficients analytically by solving two coupled wave amplitude equations in the electron cyclotron range of frequencies. The results are applicable to electron Bernstein wave heating of plasmas with two-dimensional inhomogeneity, e.g. spherical tokamaks.
A four dimensional systematic mathematical approach for investigating propagation and coupling of wave modes in a slowly varying (in all space directions and time) anisotropic, absorbing plasma is represented. The formalism is especially useful for energy considerations of the waves. It is applicable to general cases of mode conversion in plasmas with general geometries of space-time and magnetic field configurations. A simple example of how this formalism can be applied to practical cases is given.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.