Plasma confinement using biased electrode in the TCABR tokamak
Plasma confinement using biased electrode in the TCABR tokamak
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DOI：
10.1088/0029-5515/45/8/005
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发表时间：
2005-08
期刊：
影响因子：
3.3
通讯作者：
I. C. Nascimento;Y. Kuznetsov;J. Severo;A. Fonseca;A. Elfimov;V. Bellintani;M. Machida;M. Heller;R. Galvão;E. Sanada;J. I. Elizondo
中科院分区：
文献类型：
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作者：
I. C. Nascimento;Y. Kuznetsov;J. Severo;A. Fonseca;A. Elfimov;V. Bellintani;M. Machida;M. Heller;R. Galvão;E. Sanada;J. I. Elizondo
本文报道了在R = 0.16 m处放置电极化电极的TCABR托卡马克（R = 0.61 m, a = 0.18 m）上获得的实验数据。实验条件为等离子体电流为90ka (q = 3.1)，注氢量调整为电子密度为1.0 × 1019 m−3，无偏置。测量了有偏差和无偏差时等离子体参数的时间演化和径向分布。结果表明，氢谱线密度增大，最大可达2.6倍，Hα氢谱线强度减小，Cⅲ杂质含量保持不变。等离子体参数的时间行为和径向分布分析表明，受限等离子体进入h模区。数据分析表明，与预测的Neo-Alcator标度律值相比，最大增强的能量约束因子为1.95，在最大密度处衰减为1.5。在等离子体边缘附近，密度梯度有瞬态增加的迹象。利用测量的浮动电位和离子饱和电流对刮擦层的湍流和输运进行计算，结果表明功率谱和输运明显下降。未观察到分岔，饱和电流在50µs内下降。
Experimental data obtained on the TCABR tokamak (R = 0.61 m, a = 0.18 m) with an electrically polarized electrode, placed at r = 0.16 m, is reported in this paper. The experiment was performed with plasma current of 90 kA (q = 3.1) and hydrogen gas injection adjusted for keeping the electron density at 1.0 × 1019 m−3 without bias. Time evolution and radial profiles of plasma parameters with and without bias were measured. The comparison of the profiles shows an increase of the central line-averaged density, up to a maximum factor of 2.6, while Hα hydrogen spectral line intensity decreases and the C III impurity stays on the same level. The analysis of temporal behaviour and radial profiles of plasma parameters indicates that the confined plasma enters the H-mode regime. The data analysis shows a maximum enhanced energy confinement factor of 1.95, decaying to 1.5 at the maximum of the density, in comparison with predicted Neo–Alcator scaling law values. Indications of transient increase of the density gradient near the plasma edge were obtained with measurements of density profiles. Calculations of turbulence and transport at the Scrape-Off-Layer, using measured floating potentials and ion saturation currents, show a strong decrease in the power spectra and transport. Bifurcation was not observed and the decrease in the saturation current occurs in 50 µs.