Magnetic flux pumping in 3D nonlinear magnetohydrodynamic simulations
Magnetic flux pumping in 3D nonlinear magnetohydrodynamic simulations
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DOI：
10.1063/1.4990704
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发表时间：
2017-06
影响因子：
2.2
通讯作者：
I. Krebs;S. Jardin;S. Gunter;K. Lackner;M. Hoelzl;E. Strumberger;N. F. M. R. C. F. P. Physics-N.-F.-M.-R.-C.-F.-P.-Physics-2140458829;Princeton Plasma Physics Laboratory;Princeton;Nj;Usa;Max Planck Institute for extraterrestrial Physics;Garching;H Germany
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作者：
I. Krebs;S. Jardin;S. Gunter;K. Lackner;M. Hoelzl;E. Strumberger;N. F. M. R. C. F. P. Physics-N.-F.-M.-R.-C.-F.-P.-Physics-2140458829;Princeton Plasma Physics Laboratory;Princeton;Nj;Usa;Max Planck Institute for extraterrestrial Physics;Garching;H Germany
利用M3D-C1程序对托卡马克装置中的一种自调节磁通抽运机制进行了分析，该机制将堆芯安全系数维持在Q≈1，从而防止锯齿现象。在这些模拟中，导致磁通泵浦的最重要的机制是饱和的(m=1，n=1)准交换不稳定性通过发电机效应在等离子体中心产生有效的负回路电压。结果表明，如果β足够高，为产生发电机回路电压的(m=1，n=1)不稳定提供必要的驱动，则在模拟中可以防止锯切现象。发电机回路电压的必要大小取决于电流密度分布集中达到峰值的趋势，而在我们的模拟中，电流密度分布由所施加的热源分布的尖峰程度控制。
A self-regulating magnetic flux pumping mechanism in tokamaks that maintains the core safety factor at q≈1, thus preventing sawteeth, is analyzed in nonlinear 3D magnetohydrodynamic simulations using the M3D-C1 code. In these simulations, the most important mechanism responsible for the flux pumping is that a saturated (m=1,n=1) quasi-interchange instability generates an effective negative loop voltage in the plasma center via a dynamo effect. It is shown that sawtoothing is prevented in the simulations if β is sufficiently high to provide the necessary drive for the (m=1,n=1) instability that generates the dynamo loop voltage. The necessary amount of dynamo loop voltage is determined by the tendency of the current density profile to centrally peak which, in our simulations, is controlled by the peakedness of the applied heat source profile.