Measurement of the electromagnetic torque in rotating DIII-D plasmas
Measurement of the electromagnetic torque in rotating DIII-D plasmas
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DOI：
10.1088/0741-3335/52/4/045013
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发表时间：
2010-04
影响因子：
2.2
通讯作者：
N. Logan;E. Strait;H. Reimerdes
中科院分区：
文献类型：
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作者：
N. Logan;E. Strait;H. Reimerdes
由于静态或旋转的磁扰动，或两者兼而有之，在旋转的DIII-D等离子体的电磁转矩的研究，通过推导出的转矩的估计，从测量的磁扰动的各种组件在壁。该方法基于麦克斯韦应力张量形式（哈钦森2001等离子体物理控制。Fusion 43 145）。对于大撕裂模的锁定，在锁定时的电磁转矩的这种测量与运动方程一致。测量和建模表明，模式旋转频率超过几百赫兹的磁扰动和石墨瓦之间的动量转移不再是可以忽略不计的，揭示了一个新的托卡马克双壁模型的必要性。计算磁场测量的瓷砖的屏蔽效果，并显示与不切实际的小扭矩在高频模式下测得的一致。电磁转矩被证明是一个重要的因素，在确定等离子体旋转在很宽的范围内的模式频率从零到千赫兹的范围。它可以与其他扭矩源相媲美，例如用于加热的切向中性束注入。
The electromagnetic torque due to either static or rotating magnetic perturbations, or both, on a rotating DIII-D plasma is studied by deriving an estimate of the torque from measurements of various components of the magnetic perturbation at the wall. This approach is based on the Maxwell stress tensor formalism (Hutchinson 2001 Plasma Phys. Control. Fusion 43 145). For the locking of large tearing modes, this measurement of the electromagnetic torque at the time of the locking is consistent with the equation of motion. Measurements and modeling show that for mode rotation frequencies above a few hundred hertz the momentum transfer between magnetic perturbations and the graphite tiles is no longer negligible, revealing the necessity for a new two-wall model of the tokamak. The shielding effect of the tiles on magnetic field measurements is calculated, and shown to be consistent with unrealistically small torques measured during high frequency modes. The electromagnetic torque proves to be an important factor in determining plasma rotation at a wide range of mode frequencies from zero to the kilohertz range. It can be comparable to other sources of torque, such as tangential neutral beam injection for heating.