Scrape-off layer radiation and heat load to the ASDEX Upgrade LYRA divertor
Scrape-off layer radiation and heat load to the ASDEX Upgrade LYRA divertor
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DOI：
10.1088/0029-5515/39/7/307
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发表时间：
1999-07
期刊：
影响因子：
3.3
通讯作者：
A. Kallenbach;M. Kaufmann;D. Coster;J. Fuchs;A. Herrmann;J. Neuhauser;R. Schneider;K. Borrass;H. Bosch;A. Carlson;J. Gafert;K. Lackner;K. Schmidtmann;J. Schweinzer;W. Suttrop;U. Wenzel
中科院分区：
文献类型：
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作者：
A. Kallenbach;M. Kaufmann;D. Coster;J. Fuchs;A. Herrmann;J. Neuhauser;R. Schneider;K. Borrass;H. Bosch;A. Carlson;J. Gafert;K. Lackner;K. Schmidtmann;J. Schweinzer;W. Suttrop;U. Wenzel
1997年，新的“LYRA”转向器在ASDEX Upgrade投入使用，同时，通过安装第二个注入器，中性束加热功率增加到20兆瓦，P/R值为12兆瓦/米。实验表明，ASDEX升级LYRA分流器能够处理如此高的加热功率。与之前的开放式分流器Div i相比，LYRA分流器中的最大热通量总体上减少了约2倍，这种减少主要是由于分流器区域内的辐射损失增加，这是由氢中性物有效反射到热分离矩阵区域造成的。辐射损失的主要渠道是碳辐射，它将分流器等离子体冷却到几个电子伏特，此时氢辐射损失变得显著。辐射损耗优先降低了分离矩阵处的功率通量，导致击点位置附近的早期分离。随着密度的增加，分离区在垂直靶上向上延伸。LYRA导流器的辐射功率约为45%，几乎与加热功率无关。该值比第i区典型辐射分数高2倍。所进行实验的B2-EIRENE模型支持实验发现，并改进了对导流区损失过程的理解。
In 1997 the new `LYRA' divertor went into operation at ASDEX Upgrade and, in parallel, the neutral beam heating power was increased to 20 MW by installation of a second injector leading to a P/R value of 12 MW/m. Experiments have shown that the ASDEX Upgrade LYRA divertor is capable of handling such high heating powers. There is an overall reduction of the maximum heat flux in the LYRA divertor by about a factor of 2 compared with the previous open divertor Div I. This reduction is mainly due to increased radiative losses inside the divertor region, which are caused by an effective reflection of hydrogen neutrals into the hot separatrix region. The main channel of radiative loss is carbon radiation, which cools the divertor plasma down to a few electronvolts, where hydrogen radiation losses become significant. The radiative losses preferentially reduce the power flux at the separatrix, leading to early detachment around the strike point position. With increasing density, the detached region extends upwards on the vertical target. The power fraction radiated in the LYRA divertor is around 45% and nearly independent of the heating power. This value is a factor of 2 higher than the typical radiation fraction in Div I. B2-EIRENE modelling of the performed experiments supports the experimental finding and refines the understanding of loss processes in the divertor region.