Three-dimensional theory of waveguide-plasma coupling

Abstract

ABSTRACT. A general, linear theory of coupling electromagnetic fields from free-space waveguide arrays to an inhomogeneous plasma in a magnetic field is presented. In contrast to previous analyses, which assumed parallel-plate waveguides, waveguides having closed cross-sections of arbitrary shape are considered; full account is taken of all the waveguide modes. Far away from the coupling region, the plasma is assumed to be absorptive and the waveguides to propagate only their dominant modes. The formulation is geared to obtain the reflection coefficients in the waveguides and the excitation of waves in the plasma. The results are applicable to RF heating of plasmas whose size is large compared to the waveguide array, as would be the case in a fusion reactor, and valid for the frequency regimes of either ion-cyclotron (harmonic), or lower-hybrid, or electron-cyclotron (harmonic) heating.

Calculation of coupling to slow and fast waves in the LHRF from phased waveguide arrays

“…The method we use to calculate waveguide array-plasma coupling has been described in detail in several previous publications [10,14,15]…”

“…The method we use to calculate waveguide arrayplasma coupling has been described in detail in several previous publications [10,14,15], so the following discussion emphasizes the aspects of the present work which are new or have not been described previously. The model array consists of an arbitrary number of identical rectangular waveguides loaded with dielectric.…”

“…Bers and Theilhaber [14] outlined a computational method which allows the removal of most of these assumptions, though no numerical work was reported. The following approximations remain: the plasma is plane-stratified, the DC magnetic field is purely toroidal, and the coupling region is treated by using cold plasma theory.…”

Modeling of lower hybrid antennas using the ALOHA code and comparisons with Tore Supra experiments

“…The ALOHA code computes the plasma coupling of all the waveguides, with an advanced implementation of the linear theory presented by Bers and Theilhaber [12]. Near the mouth of the antenna, the evanescent modes which can be excited are taken into account and it is assumed that the launcher is opened through a infinite perfect electric conducting surface.…”

Calculation of the high and low prices of options by means of completion of the market

“…Following Bers and Theilhaber [9], we introduce the plasma surface admittance for the fast wave as Y zy (k y , k z ) = H z /E y , where the Fourier transforms of the fields are evaluated at the plasma-launcher interface.…”