Tungsten transport and sources control in JET ITER-like wall H-mode plasmas
Tungsten transport and sources control in JET ITER-like wall H-mode plasmas
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DOI：
10.1016/j.jnucmat.2014.12.044
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发表时间：
2015-08
影响因子：
3.1
通讯作者：
N. Fedorczak;P. Monier-Garbet;T. Pütterich;S. Brezinsek;P. Devynck;R. Dumont;M. Goniche;E. Joffrin-E.
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文献类型：
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作者：
N. Fedorczak;P. Monier-Garbet;T. Pütterich;S. Brezinsek;P. Devynck;R. Dumont;M. Goniche;E. Joffrin-E.
从钨源和传输的控制能力方面，研究了用喷射式ITER壁进行的一组放电。在附着式偏滤器区域，气体喷注的增加会导致更高的偏滤器循环离子通量，更低的偏滤器钨源，更高的ELM频率和更低的以钨离子为主的核心等离子体辐射。榆树的底座冲洗和偏滤器屏蔽(包括再沉积)可能都是原因。对于特定的场景，可以使用等离子体垂直位置的Kick来增加ELM频率，从而导致略低的核心辐射。在等离子体中心采用离子回旋射频加热，有效地提高了中心电子温度梯度，使电子密度分布平坦化，使中心钨峰值显著降低。主腔内的铍蒸发并没有减少局部偏滤器的钨源，而堆芯辐射却减少了约50%。
A set of discharges performed with the JET ITER-like wall is investigated with respect to control capabilities on tungsten sources and transport. In attached divertor regimes, increasing fueling by gas puff results in higher divertor recycling ion flux, lower divertor tungsten source, higher ELM frequency and lower core plasma radiation, dominated by tungsten ions. Both pedestal flushing by ELMs and divertor screening (including redeposition) are possibly responsible. For specific scenarios, kicks in plasma vertical position can be employed to increase the ELM frequency, which results in slightly lower core radiation. The application of ion cyclotron radio frequency heating at the very center of the plasma is efficient to increase the core electron temperature gradient and flatten electron density profile, resulting in a significantly lower central tungsten peaking. Beryllium evaporation in the main chamber did not reduce the local divertor tungsten source whereas core radiation was reduced by approximately 50%.