A feasibility study for a Doppler Reflectometer System in the JT-60SA tokamak

TL;DR

This study assesses the feasibility of installing a Doppler reflectometer system in the JT-60SA tokamak, demonstrating potential designs and installation strategies to support advanced plasma diagnostics.

Contribution

It provides a detailed feasibility analysis and conceptual design options for a Doppler reflectometer in JT-60SA, addressing scientific and technical requirements.

Findings

Feasibility of probing core and edge plasma regions

Design options for minimal and baseline systems

Installation within a small port is viable

Abstract

In this work we present a study on the viability and practicality of installing a Doppler reflectometer (DR) system in the JT-60SA advanced tokamak. First, we discuss its scientific scope in the context of the JT-60SA research plan. We identify a number of fields in which a DR would be very relevant for the accomplishment of said plan and outline a scientific program for the diagnostic. Then, starting from a number of design hypothesis, we use a ray tracing code to carry out a feasibility study for a number of relevant scenarios and identify a geometric solution for the installation of a DR such that both core and edge can be probed in the prescribed wave number range, thus achieving the proposed scientific objectives. Finally, we perform a preliminary discussion on the different possibilities for a conceptual design (including a minimum viable system and a baseline system) and their requirements in terms of components and space. We conclude that a viable conceptual design could be carried out using a small fraction of a horizontal port, leaving room for additional diagnostic systems.