Equilibrium properties of spherical torus plasmas in NSTX
Equilibrium properties of spherical torus plasmas in NSTX
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DOI：
10.1088/0029-5515/41/11/309
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发表时间：
2001-11
期刊：
影响因子：
3.3
通讯作者：
S. Sabbagh;S. Kaye;J. Menard;F. Paoletti;M. Bell;R. Bell;J. Bialek;M. Bitter;E. Fredrickson-E.-Fredr
中科院分区：
文献类型：
--
作者：
S. Sabbagh;S. Kaye;J. Menard;F. Paoletti;M. Bell;R. Bell;J. Bialek;M. Bitter;E. Fredrickson-E.-Fredr
NSTX 的研究旨在建立用于高 δ 辅助加热实验的球形环面等离子体。该器件的长半径 R0 = 0.86μm，中平面半宽度为 0.7μm。它已在环形磁场 B0 ? 下运行。 0.3?T 和 Ip ？ 1.0?MA。使用 EFIT 代码的自动化版本分析放电之间等离子体平衡的演变。限制器、双零点和较低的单零点转向配置已持续数次能量限制。通过中性束加热，等离子体存储能量达到 92?kJ (?t = 17.8%)。等离子体伸长率在 1.6 ? ？ ？ 2.0 和 0.25 范围内的三角形？ ？ ？ 0.45 一直维持，值为 ? = 2.6 和？ = 0.6 暂时达到。重建的磁信号以低误差拟合到相应的测量值。非磁性诊断的测量结果支持等离子体边界、压力和安全系数曲线的各个方面。氘和氦等离子体的等离子体密度分别达到格林沃尔德极限的 0.8 和 1.2 倍，但没有遇到明确的极限。不稳定性包括锯齿和重新连接事件，其特征是米尔诺夫振荡和 Ip 的扰动，？和li的演变，已被观察到。观察到低 q 限制，这是由低环形模数扭结不稳定性造成的。
Research in NSTX has been conducted to establish spherical torus plasmas to be used for high ?, auxiliary heated experiments. This device has a major radius R0 = 0.86?m and a midplane halfwidth of 0.7?m. It has been operated with toroidal magnetic field B0 ? 0.3?T and Ip ? 1.0?MA. The evolution of the plasma equilibrium is analysed between discharges with an automated version of the EFIT code. Limiter, double null and lower single null diverted configurations have been sustained for several energy confinement times. The plasma stored energy reached 92?kJ (?t = 17.8%) with neutral beam heating. A plasma elongation in the range 1.6 ? ? ? 2.0 and a triangularity in the range 0.25 ? ? ? 0.45 have been sustained, with values of ? = 2.6 and ? = 0.6 being reached transiently. The reconstructed magnetic signals are fitted to the corresponding measured values with low errors. Aspects of the plasma boundary, pressure and safety factor profiles are supported by measurements from non-magnetic diagnostics. Plasma densities have reached 0.8 and 1.2 times the Greenwald limit in deuterium and helium plasmas, respectively, with no clear limit encountered. Instabilities including sawteeth and reconnection events, characterized by Mirnov oscillations, and a perturbation of the Ip, ? and li evolutions, have been observed. A low q limit was observed and is imposed by a low toroidal mode number kink instability.