A Model of Peaked Density Profile and Inward Pinch in Tokamaks
A Model of Peaked Density Profile and Inward Pinch in Tokamaks
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托卡马克峰值密度分布和向内收缩模型
DOI：
10.1143/jpsj.59.3431
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
S. Itoh
中科院分区：
文献类型：
--
作者：
S. Itoh
提出了托卡马克欧姆放电的向内挤压和峰值密度分布模型理论。在剪切旋转的情况下，离子的反常粘度导致了在磁场中的漂移。径向电场E r也能引起电子向内的挤压。黏度与扩散系数的比值，即普朗特数，决定了稳态E r的结构和密度分布n (r)。在粘性等离子体中，密度和旋转速度都有峰值。边缘中性的减少改变了边界条件，可以引起进一步的密度峰值。d E r /d r的变化向中心传播，引起与速度剪切阻尼有关的离子粘性加热。
A model theory of inward pinch and peaked density profile of ohmic discharges in the tokamak is presented. Ion anomalous viscosity in the presence of sheared rotation causes the drift across the magnetic field. Radial electric field, E r , can cause an inward pinch of electrons as well. The ratio of viscosities and the diffusion coefficient, the Prandtl number, determines the structures of E r and the density profile n ( r ) in a stationary state. In viscous plasmas, peaked profiles of both density and rotation velocity are expected. Reduction of edge neutrals changes the boundary condition and can induce further density peaking. Change of d E r /d r propagates into the center, causing ion viscous heating associated with the damping of velocity shear.