Snake perturbations during pellet injection and LHCD in the HL-1M tokamak

Autor:	Yinjia Zheng, Yi Liu, Jiafu Dong, Gangcheng Guo, Yong Liu, Enyao Wang, Zhengui Xiao, Xiaoming Qiu, Yunzhe Zhong, Bingzhong Fu, Yunbo Dong
Rok vydání:	2004
Předmět:	Materials science Tokamak Oscillation digestive oral and skin physiology Magnetic confinement fusion Plasma Sawtooth wave Condensed Matter Physics Plasma oscillation complex mixtures law.invention Nuclear Energy and Engineering law Plasma diagnostics Atomic physics Excitation
Zdroj:	Plasma Physics and Controlled Fusion. 46:455-470
ISSN:	1361-6587 0741-3335
DOI:	10.1088/0741-3335/46/3/003
Popis:	Excitation of snake perturbations has been observed in the core region of pellet-fuelled HL-1M plasmas when the pellets cross the surface with a q value of 1. It is observed that the snake oscillations have an m = 1, n = 1 helicity with quite a long lifetime. A detailed comparison has been made between the locations of the q = 1 surface and the snake oscillation. Through measurements of the plasma q-profile by means of multi-exposures with a CCD camera during pellet ablation, and investigation of the pellet ablation process, possible mechanisms for the formation of the snake oscillation are discussed. In addition, a large, long-lived snake-like oscillation is frequently observed in lower-hybrid current driven (LHCD) discharge in which the sawtooth has been stabilized early in the discharge. There is evidence that such a perturbation is due to impurity accumulation during sawtooth-stabilization, and good performance with peaking profiles after LHCD is limited by magnetohydrodynamic instabilities including sawtooth and snake activities in HL-1M plasmas.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::f9f356b0a8dbc31d0ba376cb133b88c4 https://doi.org/10.1088/0741-3335/46/3/003 Zobrazit plný text záznamu