Summary of Papers on ECRH Experiments

Abstract

The presentations on ECRH experiments presented in EC-17 are summarized. Real time control, feedback control One of the hot topics of ECRH experiment discussed in this workshop was real time control or feed back control fully utilizing local controllability and fast time response of the ECRH system. The real time system for MHD activity control in the FTU tokamak is presented by C. Sozzi, where the several hardware and control argolism for the feedback control of MHD activities (sawtooth, NTM) are implemented and initial test was successfully executed. Related series of papers on FTU are presented by E. Alessi, C. Galperti and A. Moro. ELM control or pacing as well as the suppression of the MHD instabilities is also a hot topic of ECRH experiment and outstanding experimental results in TCV are presented by F. Ferici and M. Lauret. Utilizing newly installed real-time antenna control system with flexible digital real time control system, sawtooth pacing, ELM pacing, NTM suppression are demonstrated. J. Lohr also reported a fine control scheme developed and executed in DIII-D using the plasma control system (PCS) and field program gate array (FPGA) witch are connected also to ECRH system allowing fast control of the injection angle and gyrotron output power. These capabilities are utilized to control plasma instabilities and secure operation of the gyrotrons as well. New fast steerable launcher and ”NTM feedback suite” (equilibrium, density profile, ray tracing, correlation analysis, mirror control) are implemented in ASDEX U are also presented in the talk of J. Stober. Feedforward test of the system were already done and waiting for the feedback control demonstration. ECH and ECCD effects on NTMs stabilization by ECRH is also investigated for JT-60SA tokamak and presented by C. Sozzi. ECRH system upgrades and demonstration of its potential In the presentations of the application of ECRH on the DIII-D Tokamak, R. Prater thoroughly reviewed potential of ECRH in the investigation of the tokamak operation and indicated the upgrading scenario of the ECRH system in the DIII-D. Topics included are the electron heating effects related to the study of plasma rotation and H-mode threshold power, Te profile control for validation of the NBCD model or RWM control , modeling ITER startup and rampdown, modifying the temperature gradient for studying the transition, trapped electron mode, and QH-mode. ECCD was applied to drive currents in the plasma in ITER demonstration steady-state discharges for radially distributed current drive in support of fully noninductive operation at high beta, control of neoclassical tearing modes for experiments on resistive wall modes in low rotation, high beta discharges, for neoclassical tearing a e-mail: kubo@lhd.nifs.ac.jp EPJ Web of Conferences DOI: 10.1051/ C © Owned by the authors, published by EDP Sciences, 2012 , epjconf 201232 / 020 (2012) 02 32 0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 01 01 Article available at http://www.epj-conferences.org or http://dx.doi.org/10.1051/epjconf/20123202001 EPJ Web of Conferences mode control using oblique electron cyclotron emission as a diagnostic to determine robustly the optimum location of the ECCD, studies of the validation of resistive MHD models and development of model-based current profile control. In accordance to the increasingly important role of the ECRH, it is reported that the ECRH system is proposed to be upgrade to total injection power up to 12 MW. In ASDEX U, J. Stober reported undergoing upgrade of multi frequency system (140/105 GHz) and injected power reached 3.9 MW at 140 GHz and 2.1 MW at 105 GHz. Such enhanced ECRH power was used for several physics studies such as H-mode optimization. In relation to the system upgrades, monitoring the stray radiation in the vacuum vessel is also an important issue and M. Schubert discussed the Sniffer probes and large area bolometer detectors. J. H. Jeong reported the successful commissioning of 170 GHz, 1MW ECH& CD system in KSTAR. High power long pulse injection experiments are expected to start soon. Detailed Physics Study