L-mode SOL width scaling in the MAST spherical tokamak
L-mode SOL width scaling in the MAST spherical tokamak
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DOI：
10.1088/0741-3335/48/8/003
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发表时间：
2006-07
影响因子：
2.2
通讯作者：
J. Ahn;G. Counsell;A. Kirk
中科院分区：
文献类型：
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作者：
J. Ahn;G. Counsell;A. Kirk
建立了球塔托卡马克(ST)L模等离子体外侧中面刮离层(SOL)热流密度宽度Δh的新数据集。研究了等离子体密度、环向磁场、溶胶层平行连接长度和隔板表面热流密度等关键等离子体参数对标度的影响。对于Δh数据集，建立了一个经验标度，它分别与连接长度(或边缘安全系数)和密度呈强正相关，与表面热流和磁场呈弱或中等程度的逆相关。将经验标度与早期对一系列常规几何托卡马克的结果进行了比较，结果表明托卡马克对密度和边缘安全系数的依赖性较弱。然而，重要的是，对表面热通量(以及加热功率)的弱负依赖在传统几何结构和ST几何结构中都是常见的。实验数据还被用来检验一些尺寸上正确的Δh标度，这些标度是由垂直输运与平行于磁场的经典输运耦合的理论模型发展而来的。基于阻性MHD交换驱动的垂直传输的缩放提供了最好的拟合，尽管有几个模型很接近。更好地拟合理论标度的子集被用来外推未来燃烧ST机器的一个设计中的Δh，并最终预测外侧偏滤器靶板上的峰值热负荷。
A new data-set of outboard mid-plane scrape-off layer (SOL) heat flux widths, Δh, has been constructed for L-mode plasmas in the MAST spherical tokamak (ST). The scaling with key plasma parameters such as density, toroidal magnetic field, parallel connection length in the SOL and surface heat flux at the separatrix is investigated. An empirical scaling is developed for the Δh data-set, which exhibits a strong positive dependence on both the connection length (or edge safety factor) and density and weak or moderate inverse dependences on the surface heat flux and magnetic field, respectively. The empirical scaling is compared with earlier results for a range of tokamaks with conventional geometry, which show weaker dependence on the density and edge safety factor. Importantly, however, the weak negative dependence on the surface heat flux (and thus heating power) is common in both conventional and ST geometries. The experimental data are also used to test a number of dimensionally correct Δh scalings developed from theoretical models for perpendicular transport in the SOL coupled with classical transport parallel to the magnetic field. A scaling based on perpendicular transport driven by resistive MHD interchange provides the best fit, although several models are close. A subset of the better fitting theoretical scalings are used to extrapolate for Δh in one design for a future burning ST machine and finally to predict the peak heat loading on the outboard divertor target plate.