Speaker
Description
We report the first applications of the quasioptical (QO) ray tracing code PARADE (PAraxial RAy DEscription) for modeling electron cyclotron emission (ECE) diagnostic. Geometrical optics (GO) has been exploited to predict the ECE intensity received into the antenna. Nevertheless, due to the fact that an actual receiving antenna has finite sensitivity not only for the line of sight direction $\zeta$ but for the transverse directions $\tilde{\varrho}^\sigma$, GO procedure, which drops the information in $\tilde{\varrho}^\sigma$ directions, cannot be enough to account for the locality of the radiations and can mis-evaluate the position and local electron temperature. Here, we focus on the fact that ECE measurement can be considered as the inverse process of electron cyclotron resonance heating (ECRH). To explore the more highly precise predictions of the ECRH, QO model accounting for the wave fields in transverse beam cross section has been developed. Hence, by exploiting the framework of the QO ray tracing code PARADE, a QO model of ECE measurement was studied. By introducing a weighting operator $\widehat{W}$ induced by the envelope profile of a wave beam virtually injected from an ECE receiving antenna, an integral equation, formally identical to the conventional GO model, is newly derived from the wave action conservation law. QO ECE prediction module -E$^3$ (Electron Emission Evaluation) is also newly developed, is applied to the JT-60SA tokamak, and shows that radiation temperature is corrected from conventional GO prediction. The -E$^3$ module and the PARADE code are applicable to any fusion plasma devices. By using this ECE prediction package, more realistic calculations of radiation temperature, carefully considering the actual structure of an ECE receiving antenna, is expected.
