The influence of random density fluctuations in a tokamak on the propagation of electromagnetic waves polarised in the ordinary mode is studied numerically. The study is of direct relevance for a proposed fast ion and a-particle diagnostic for JET relying on collective scattering of intense millimetre waves. The wave propagation is studied in the limit of geometrical optics by a ray-tracing code. For overall parameters specified by the contract, it is found that even low levels of relative density fluctuations may lead to a substantial broadening of an incoming wave beam. This effect is particularly pronounced for high values of the central plasma density. The wave beam broadening due to density fluctuations could lead to a degradation in the performance of the proposed diagnostic by limiting its spatial resolution.
|Place of Publication||Roskilde|
|Publisher||Risø National Laboratory|
|Number of pages||24|
|Publication status||Published - 1988|