Lower hybrid current drive experiments in support of high confinement long pulse operation in EAST

Annika Ekedahl,Jinping Qian,Xiaojie Wang,Chengming Qin,Bojiang Ding,Fukun Liu,Yves Peysson,Xiao-Lan Zou,Yanping Zhao,Yuantao Song,Julien Hillairet,Xianzu Gong,Tuong Hoang,Xinjun Zhang,Marc Goniche,Miaohui Li,J Hillairet

doi:10.1051/epjconf/201715703011

Abstract

The lower hybrid current drive (LHCD) system plays a crucial role in the mission of the Experimental Advanced Superconducting Tokamak (EAST) and is a prerequisite for reaching long pulse, high confinement plasmas on EAST [1, 2]. LHCD experiments and modelling [3] have been carried out on EAST in 2015-2016, with the aim to optimising EAST long pulse scenarios, and at the same time gain experience for the exploitation of WEST [4]. Experiments have been carried out to study the LH current drive efficiency in different plasma configurations (Upper Single Null and Lower Single Null). The effect of the gas feed location on the LH wave coupling was investigated by comparing gas fuelling from high field side, low field side and upper divertor. In view of long pulse H-mode scenarios, a series of H-mode experiments were conducted where all the heating power was provided by RF heating methods only, i.e. LHCD, ECRH and ICRH. H-modes were sustained in both Upper Single Null (W divertor) and Lower Single Null (carbon divertor) configurations, with loop voltage maintained as low as 50 mV.

Highlights

The radiofrequency (RF) heating and current drive systems play a crucial role in the mission of the Experimental Advanced Superconducting Tokamak (EAST) and are prerequisites for reaching long pulse, high-confinement (H-mode) plasmas on EAST [1, 2]
This paper reports on Lower Hybrid Current Drive (LHCD) experiments and modelling carried out on EAST in 2015-2016, within the framework of the Associated Laboratory ASIPP-IRFM, with the aim to optimize EAST long pulse scenarios, and at the same time gain experience before the exploitation of the WEST device [4]
In view of long pulse Hmode scenarios, a series of H-mode experiments has been conducted where all the heating power was provided by RF heating methods only, i.e. LHCD, ECRH (Electron Cyclotron Resonance Heating) and ICRH (Ion Cyclotron Resonance Heating)

Summary

Introduction

The radiofrequency (RF) heating and current drive systems play a crucial role in the mission of the Experimental Advanced Superconducting Tokamak (EAST) and are prerequisites for reaching long pulse, high-confinement (H-mode) plasmas on EAST [1, 2]. This paper reports on LHCD experiments and modelling carried out on EAST in 2015-2016, within the framework of the Associated Laboratory ASIPP-IRFM, with the aim to optimize EAST long pulse scenarios, and at the same time gain experience before the exploitation of the WEST device [4]. In view of long pulse Hmode scenarios, a series of H-mode experiments has been conducted where all the heating power was provided by RF heating methods only, i.e. LHCD, ECRH (Electron Cyclotron Resonance Heating) and ICRH (Ion Cyclotron Resonance Heating). In addition to the experimental results presented here, EAST experiments have revealed some operational

LH wave coupling

LH wave propagation effects

H-mode experiments

Findings

Summary