论文标题

融合等离子体中的双重位置加油的沙珀模型

Sandpile modelling of dual location fuelling in fusion plasmas

论文作者

Bowie, C. A., Hole, M. J.

论文摘要

我们修改了Chapman SandPile模型(Chapman \ TextIt {et al} \ TextIt {物理评论Letters} 86,2814(2001))与Pellet起搏形成比较,该比较用于减少或消除Fusion Plasma中的ELMS。我们采用了该模型的一种变体,其中引入了带有反馈的基座(Bowie and Hole \ TextIt {Phys。Polasmas} 25,012511(2018)),我们进一步修改以提供双燃料 - 在沙皮中的中心和边缘附近添加了砂。我们观察到,当在基座顶部添加额外的沙子时,MLE会在很大程度上被抑制。尽管这种抑制是通过减少总能量限制而产生的,但该降低低于MLE大小的减小。 MLE抑制和减少能量限制之间的权衡不仅取决于额外的沙子量,还取决于其相对于基座顶部的精确位置。我们建议,恒定双重加油的方法可能同样适用于等离子体,并且可能建议在融合等离子体中抑制ELM的策略。我们观察到,当提出的额外沙子数量在“颗粒”中添加时,使用基于提议的ITER抑制ELM抑制的频率和量,MLE的频率和数量类似地被抑制,尽管当小球速率没有基本上超过MLE频率时,MLE并未受到显着抑制。这表明,小球大小和高频的基座顶部的小球注射可能代表了我们所提出的方案的合理物理代理。但是,我们的结果表明,这不是颗粒与榆树频率的同步,而是在这种制度中抑制ELM的关键因素,而是在基座顶部引入额外的加油。

We modify the Chapman sandpile model (Chapman \textit{et al} \textit{Physical Review Letters} 86, 2814 (2001)) to form comparisons with pellet pacing, which is used to reduce or eliminate ELMs in a fusion plasma. We employ a variation of that model in which a pedestal with feedback is introduced (Bowie and Hole \textit{Phys. Plasmas} 25, 012511 (2018)), which we further modify to provide for dual fuelling - sand is added both at the centre of the sandpile, and near the edge. We observe that when the additional sand is added at the top of the pedestal, MLEs are largely suppressed. While this suppression comes at a cost by way of reduction in total energy confinement, that reduction is lower than the reduction in MLE size. The trade-off between MLE suppression and reduction in energy confinement depends not only on the amount of extra sand, but also on its precise location relative to the top of the pedestal. We suggest that the approach of constant dual fuelling may be equally applicable to plasmas, and may suggest a strategy for ELM suppression in fusion plasmas. We observe that when the proposed amount of extra sand is added in 'pellets', using frequencies and amounts based on those proposed for ELM suppression for ITER, MLEs are similarly suppressed, although MLEs are not significantly suppressed when the pellet rate does not substantially exceed the MLE frequency. This suggests that pellet injection at the top of the pedestal at small pellet size and high frequency may represent a reasonable physical proxy for our proposed scheme. However, our results suggest that it is not the synchronisation of pellets to ELM frequencies which is the key factor for ELM suppression in this regime, but rather the introduction of additional fuelling at the top of the pedestal.

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