Regensburg 2016 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 6: Focus Session: Applications of Dielectric Materials in Microwave Technology

DF 6.4: Topical Talk

Montag, 7. März 2016, 16:20–16:50, H26

Double-disc Diamond Windows for Fusion Applications — •Alessandro Vaccaro, Gaetano Aiello, Giovanni Grossetti, Francesco Mazzocchi, Andreas Meier, Theo Scherer, Sabine Schreck, Peter Spaeh, and Dirk Strauss — Karlsruhe Institute of Technology (Institute of Applied Materials), P.O. Box 3640 76021 Karlsruhe Germany

Diamond windows are employed in Electron-Cyclotron Heating & Current Drive (EC H&CD) systems in fusion devices. By injecting high-power mm-waves beams, these systems heat up the plasma and counteract the formation of instabilities. Acquiring a complete understanding of what happens during operation of diamond windows is an important task. In fact, such units handle powers in the order of Megawatts and therefore small resonant cavities can easily become sources of high-intensity localized heating.

In this paper, we investigate a unit with a double-disc configuration. The study aims to evaluate localized power deposition on the unit's cooling channels and is carried out by developing a ray-tracing code that uses a hybrid approach; our code accounts for the waves' phase and thus reproduces the effects of interference. This goal is achieved by calculating reflection/transmission coefficients under the hypothesis of thin films and applying them only to the incident and back-refracted waves. The results show that mm-wave beams in off-axis position are potentially responsible of high heat flux deposition on the cooling channels that can, in turn, trigger nucleated boiling of the cooling water.