Properties of plasma radiation during discharges with improved confinement on HL-2A Tokamak

doi:10.1088/1674-1056/19/11/115201

摘要/Abstract

摘要： In the recent experiment on the HL-2A tokamak, two types of improved confinement regimes have been achieved in different configurations. One is the improved confinement regime in limiter configuration during electron cyclotron resonant heating (ECRH), characterized by a sharp decrease in H_α emission accompanied by an increase in the total radiation of plasma, the line averaged electron density and the stored energy of plasma. The other is high confinement regime (H-mode) in divertor configuration during a combination of ECRH and Neutral beam injection (NBI) heating, characterized with edge localized modes (ELMs) besides the features mentioned above. The ELMs are found to be localized on the plasma edge (r/a ≥ 0.8), causing average losses of particles and stored energy in the ranges of about 1--3% and 3--5% respectively during a single ELM event. So far, the ELMs observed in the HL-2A are type III ELMs with low amplitude and high repetition frequency in a range from 200 Hz to 350 Hz. An investigation of the radiated power density profiles shows that radiative cooling effect plays a significant role in the transition back to the L-mode and the triggering of ELM events.

Abstract: In the recent experiment on the HL-2A tokamak, two types of improved confinement regimes have been achieved in different configurations. One is the improved confinement regime in limiter configuration during electron cyclotron resonant heating (ECRH), characterized by a sharp decrease in H_α emission accompanied by an increase in the total radiation of plasma, the line averaged electron density and the stored energy of plasma. The other is high confinement regime (H-mode) in divertor configuration during a combination of ECRH and Neutral beam injection (NBI) heating, characterized with edge localized modes (ELMs) besides the features mentioned above. The ELMs are found to be localized on the plasma edge (r/a ≥ 0.8), causing average losses of particles and stored energy in the ranges of about 1–3% and 3–5% respectively during a single ELM event. So far, the ELMs observed in the HL-2A are type III ELMs with low amplitude and high repetition frequency in a range from 200 Hz to 350 Hz. An investigation of the radiated power density profiles shows that radiative cooling effect plays a significant role in the transition back to the L-mode and the triggering of ELM events.

Key words: improved confinement, edge localized modes, radiative cooling effect

中图分类号: (Transport properties)

52.25.Fi

52.50.Gj (Plasma heating by particle beams) 52.50.Sw (Plasma heating by microwaves; ECR, LH, collisional heating) 52.55.Fa (Tokamaks, spherical tokamaks) 52.55.Rk (Power exhaust; divertors) 52.80.-s (Electric discharges)

高金明, 刘仪, 李伟, 崔正英, 周艳, 黄渊, 季小全. Properties of plasma radiation during discharges with improved confinement on HL-2A Tokamak[J]. 中国物理B, 2010, 19(11): 115201-115202.

Gao Jin-Ming(高金明), Liu Yi(刘仪), Li Wei(李伟), Cui Zheng-Ying(崔正英), Zhou Yan(周艳), Huang Yuan(黄渊), and Ji Xiao-Quan(季小全). Properties of plasma radiation during discharges with improved confinement on HL-2A Tokamak[J]. Chin. Phys. B, 2010, 19(11): 115201-115202.

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