Confinement and exhaust in the Mega Ampere Spherical Tokamak
Confinement and exhaust in the Mega Ampere Spherical Tokamak
复制标题
兆安球形托卡马克装置中的约束和排气
DOI：
10.1088/0741-3335/44/12b/303
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发表时间：
2002
影响因子：
2.2
通讯作者：
Y. Yang
中科院分区：
文献类型：
--
作者：
G. Counsell;J. Ahn;R. Akers;E. Arends;R. Buttery;A. Field;M. Gryaznevich;P. Helander;A. Kirk;H. Meyer;M. Valovic;H. Wilson;Y. Yang
巨安培球托卡马克(MAST)目前正在进入相对于国际标度具有高归一化约束的区域，HH(IPB98(y，2))>；~1在高归一化密度下，e>；60%的Greenwald密度。Mast H-Modes的数据表明，国际约束和L-H阈值标度的高宽比依赖关系可能需要修改，以改进对ITER的预测。偏滤器的磁几何形状和燃料位置对进入桅杆上的H模有很大的影响，偏滤器的磁几何形状和燃料位置对边缘传输势垒的形成有很大的影响，在对称的连通双零构型附近的操作和极面局域的内侧气体喷发有助于边缘传输势垒的形成。桅杆上的榆树在本质上似乎是III型的，即使在最高性能的等离子体中也是如此，并具有最大的可用辅助加热功率。到目前为止，榆树的能量损失不到储存能量的4%。这些III型ELM与底座密度的降低有关，但底座温度或温度分布没有显著变化，表明能量从底座区域被传递到刮除层。对观察到的到达偏滤器目标的能量的分析表明，ELM损失主要在低场一侧。ELM外流在离等离子体边缘20厘米的外侧中面被观测到，并且与平均速度为1.2KM的地物的径向运动有关，S−1。
The Mega Ampere Spherical Tokamak (MAST) is now accessing regimes with high normalized confinement relative to international scalings, HH(IPB98(y, 2))>~1 at high normalized density, e>60% of the Greenwald density. Data from MAST H-modes suggest that the aspect ratio dependency of international confinement and L–H threshold scalings may need to be modified to improve predictions for ITER. Access to H-mode on MAST is strongly affected by both the divertor magnetic geometry and fuelling location, with the formation of an edge transport barrier being facilitated by operation near the symmetric, connected double-null configuration and with poloidally localized inboard gas puffing. The ELMs on MAST appear to be Type III in nature, even in the highest performance plasmas and with the maximum available auxiliary heating power. ELM energy losses are less than 4% of stored energy in all regimes so far explored. These Type III ELMs are associated with a reduction in the pedestal density but no significant change in the pedestal temperature or temperature profile, indicating that energy is convected from the pedestal region into the scrape-off layer. Analysis of the energy observed to arrive at the divertor targets indicates that ELM losses are predominantly on the low field side. ELM effluxes are observed up to 20 cm from the plasma edge at the outboard mid-plane and are associated with the radial motion of a feature at an average velocity of 1.2 km s−1.