An Algorithm for the Analysis of Inductive Antennas of Arbitrary Cross Section for Heating in the Ion Cyclotron Range of Frequencies

Abstract

MASTER AbstractThe application of Ion Cyclotron Range of Frequency (ICRF) heating to near ignited plasmas will require launching structures that will be capable of withstanding the harati plasma environment* The recessed antenna configuration is expected to provide sufficient protection for the structure, but to date no analysis has been done to determine if adequate coupling can be achieved in such a configuration.In this work we present a method for determining the current distribution for the antenna in the direction transverse to current flow and predict antenna loading in the presence of plasma. Antennas of arbitrary cross section are analyzed above ground planes of arbitrary shape.Results from ANDES, the ANtenna DESign code, are presented and compared to experimental results.

Measurements of electromagnetic waves in Phaedrus-B: Bench-mark test of ANTENA wave field calculations

“…The agreement between the measured and predicted values suggests that ANTENA can successfully model the antenna structure, including the finite current strap size and the current feeds, although the self-consistent current distribution remains an open question [21]. These non-ideal effects may be important in other devices and are difficult to treat analytically.…”

Global ICRF wave propagation in edge plasma and Faraday shield regions

“…Defining the vector and scalar potentials A and 0 respectively, (10) and choosing the Coulomb (radiation or transverse) gauge, -hXA z ) + = 0 (11) Eqs ( 6) and ( 7) become, using…”

“…The current in the driving antenna is Fourier expanded in Z as Ideally, Jk z (X, Y) should be calculated self-consistently with the near-field wave solution [10]. In the absence of such a self-consistent determination, an experimen-.…”

“…More recently, propagation in the equatorial plane of a tokamak has been considered [9], but uniformity in the y-direction (poloidal direction) has been assumed. Finally, Lehrman and Colestock [10] consider vacuum evanescent fields in the quasi-static limit for a slab plasma that is uniform in y. Fields are evanescent up to a plasma surface where propagation is taken into account through the boundary conditions.…”

“…Fields are evanescent up to a plasma surface where propagation is taken into account through the boundary conditions. Both the antenna loading and the current distribution in z are determined self-consistently [10] for a plasma that is completely absorbing. The analysis of Lehrman and Colestock does consider linear density gradients, but there is no wave calculation in the plasma.…”