An upgraded electron cyclotron emission imaging （ECEI） system consisting of new optics lenses with necessary electronics for receiving and processing signals for two dimension （2D） ECEI diagnostics was installed o...An upgraded electron cyclotron emission imaging （ECEI） system consisting of new optics lenses with necessary electronics for receiving and processing signals for two dimension （2D） ECEI diagnostics was installed on EAST. Hyperboloid lens were adopted in the new system to optimize the spatial resolutions. The mixers array of sixteen elements measured the plasma electron cyclotron emission at eight frequencies simultaneously, and the profiles of the electron temperature and its fluctuation in an area of 20 cm （vertical） × 6 cm （horizontal） could then be analyzed. Evolution of sawtooth precursor and crash in EAST was observed.展开更多
We investigate the possibility of the usage of displaced current in Langmuir probe measurement theoretically and experimentally.The displaced current flows through the self-generated or artificial capacitance of the r...We investigate the possibility of the usage of displaced current in Langmuir probe measurement theoretically and experimentally.The displaced current flows through the self-generated or artificial capacitance of the reference electrode under an alternative sweep voltage.It can increase the total current afforded by the reference electrode,and eliminate the interference deriving from the finite plasma sheath resistance of the reference electrode.The results in both theory and experiment lead to the conclusion that the usage of displaced current is valid and more efficient with a floating probe method.This method is applied in some harsh plasma environments when the grounded chamber wall can easily be contaminated by the dielectric.展开更多
基金supported by the National Basic Research Program of China (No. 2008CB717800)National Natural Science Foundation of China (No. 10335060)+2 种基金Grants from the Ministry of Education and the Chinese Academy of SciencesCAS-JSPS Core University Program in Plasma and Nuclear Fusionby the PRC-US Fusion Cooperation Program (Plasma Physics, Project A-5)
文摘An upgraded electron cyclotron emission imaging （ECEI） system consisting of new optics lenses with necessary electronics for receiving and processing signals for two dimension （2D） ECEI diagnostics was installed on EAST. Hyperboloid lens were adopted in the new system to optimize the spatial resolutions. The mixers array of sixteen elements measured the plasma electron cyclotron emission at eight frequencies simultaneously, and the profiles of the electron temperature and its fluctuation in an area of 20 cm （vertical） × 6 cm （horizontal） could then be analyzed. Evolution of sawtooth precursor and crash in EAST was observed.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10675121,10705028 and 10835009the ITER Domestic Program of China under Grant Nos 2009GB107000 and 2010GB107000.
文摘We investigate the possibility of the usage of displaced current in Langmuir probe measurement theoretically and experimentally.The displaced current flows through the self-generated or artificial capacitance of the reference electrode under an alternative sweep voltage.It can increase the total current afforded by the reference electrode,and eliminate the interference deriving from the finite plasma sheath resistance of the reference electrode.The results in both theory and experiment lead to the conclusion that the usage of displaced current is valid and more efficient with a floating probe method.This method is applied in some harsh plasma environments when the grounded chamber wall can easily be contaminated by the dielectric.
