Sustained Spheromak Physics Experiment (SSPX): design and physics results
Sustained Spheromak Physics Experiment (SSPX): design and physics results
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DOI：
10.1088/0741-3335/54/11/113001
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发表时间：
2012-11
影响因子：
2.2
通讯作者：
E. Hooper;R. Bulmer;B. Cohen;D. Hill;C. T. Holcomb;B. Hudson;H S McLean;L. Pearlstein;C. Romero-Talamas;C. Sovinec;B. Stallard;R. Wood;S. Woodruff
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文献类型：
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作者：
E. Hooper;R. Bulmer;B. Cohen;D. Hill;C. T. Holcomb;B. Hudson;H S McLean;L. Pearlstein;C. Romero-Talamas;C. Sovinec;B. Stallard;R. Wood;S. Woodruff
持续球膜物理实验 (SSPX) 是通过同轴螺旋注入 (CHI) 形成的高温（Te 高达 0.5 keV）球膜，在高电流形成阶段后等离子体持续时间为几毫秒。通过烘烤、放电清洁和壁上钛沉积的结合，获得了清洁的壁和低杂质操作，从而产生了高质量的等离子体。以实验为基准的电阻磁流体动力学模拟被用来阐明物理原理。确定了与 CHI 相关的 nφ = 1 环形模式的详细特性，以及形成和维持球体的非线性电流驱动和磁重联的物理原理。如果在形成后降低螺旋注入速率，则等离子体变得相对静止并且形成磁性表面。测得的核心热扩散率低至~1 m2 s−1。然而，在 CHI 建立或维持等离子体电流期间的重新连接事件被发现会打开整个等离子体的磁性表面，从而使能量快速损失到壁上。因此，SSPX 中的实验和模拟没有发现通过 CHI 和良好的能量限制同时维持的途径。本综述还介绍了其他物理结果。
The Sustained Spheromak Physics Experiment (SSPX) was a high-temperature (Te up to 0.5 keV) spheromak formed by coaxial helicity injection (CHI) and with plasma duration of a few milliseconds following the high-current formation stage. Clean walls and low impurity operation were obtained by a combination of baking, discharge cleaning and titanium deposition on the walls, allowing the generation of high-quality plasmas. Resistive-magnetohydrodynamic simulations, benchmarked to the experiment, were used to elucidate the physics. The detailed characteristics of the nφ = 1 toroidal mode associated with CHI were determined as was the physics of the nonlinear current drive and magnetic reconnection that formed and sustained the spheromak. If the helicity injection rate was reduced following formation the plasma became relatively quiescent and magnetic surfaces formed. The measured thermal diffusivity in the core was as low as ∼1 m2 s−1. However, reconnection events during buildup or sustainment of the plasma current by CHI were found to open magnetic surfaces throughout the plasma allowing rapid energy loss to the walls. As a result, experiments and simulations in SSPX found no path to simultaneous sustainment by CHI and good energy confinement. Additional physics results are also presented in this review.