Overview of the ITER EC H&CD system and its capabilities

Abstract

The Electron Cyclotron (EC) system for the ITER tokamak is designed to inject ≥20 MW RF power into the plasma for Heating and Current Drive (H&CD) applications. The EC system consists of up to 26 gyrotrons (between 1 to 2 MW each), the associated power supplies, 24 transmission lines and 5 launchers. The EC system has a diverse range of applications including central heating and current drive, current profile tailoring and control of plasma magneto-hydrodynamic (MHD) instabilities such as the sawtooth and neoclassical tearing modes (NTMs). This diverse range of applications requires the launchers to be capable of depositing the EC power across nearly the entire plasma cross section. This is achieved by two types of antennas: an equatorial port launcher (capable of injecting up to 20 MW from the plasma axis to mid-radius) and four upper port launchers providing access from inside of mid radius to near the plasma edge. The equatorial launcher design is optimized for central heating, current drive and profile tailoring, while the upper launcher should provide a very focused and peaked current density profile to control the plasma instabilities.The overall EC system has been modified during the past three years taking into account the issues identified in the ITER design review from 2007 and 2008 as well as integrating new technologies. This paper will review the principal objectives of the EC system, modifications made during the past two years and how the design is compliant with the principal objectives.

On recent results in the modelling of neoclassical-tearing-mode stabilization via electron cyclotron current drive and their impact on the design of the upper EC launcher for ITER

“…The electron-cyclotron (EC) heating and current drive (CD) system envisaged for ITER consists of two launchers, an equatorial launcher (EL) designed primarily for central heating, current drive and profile tailoring, and an upper launcher (UL) whose main goal is the control of magnetohydrodynamical instabilities, in particular the neoclassical tearing mode (NTM) and the sawtooth instability [1]. The power is provided by 24 gyrotrons delivering 1 MW each (with optional upgrade to 2 MW in a later phase) at a frequency of 170 GHz.…”

Design of a steerable launcher for the ECH system on KSTAR

“…An ECH/ECCD system is required for localized plasma heating, plasma startup for large superconducting tokamak device, preionization for low voltage startup, non-inductive current drive, and discharge cleaning of a vacuum vessel [1][2][3]. Recently, ECH/ECCD system is used in MHD instability modes control such as suppression of neoclassical tearing mode (NTM), control of sawtooth and internal transport barriers for high-performance and stability of the plasma [4][5][6]. One of advantage of ECH/ECCD system is localizing the deposited power.…”

A study of mode purity improvement in the ITER relevant transmission line

“…Single EL procured by Japan and 4 ULs procured by EU will be installed into the equatorial port and the upper port of ITER vacuum vessel. [5][6][7] The improvement of transmission mode purity in TL is one of the key issues in ITER EC system. Since all the EC components in ITER are designed to minimize its loss to achieve the specification in ITER, high mode purity is strongly required.…”