A Revised Neutral Gas Shielding Model for Pellet-Plasma Interactions
A Revised Neutral Gas Shielding Model for Pellet-Plasma Interactions
复制标题
改进的颗粒-等离子体相互作用的中性气体屏蔽模型
DOI：
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发表时间：
1978
影响因子：
1.5
通讯作者：
C. A. Foster
中科院分区：
文献类型：
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作者：
S. Milora;C. A. Foster
一个修正的中性分子烧蚀模型被导出来描述固体氢球在托卡马克等离子体中的蒸发。采用的方法是基于帕克斯、特恩布尔和福斯特的理论，他们假设小球周围的氢分子云保护表面不受进入的高能电子的影响，这样做可以调节蒸发速率。这种处理方法与早期模型的不同之处在于，在分析分子云的流体动力学行为时，没有援引物质从表面流出的假设，即到处都是声波。流体动力学方程的数值解（包括气体中局部强电子加热的影响）表明，相对于Parks等人的解，物质离开球团的流动最初是缓慢的，然后迅速加速和变细。这种行为在温度较高的等离子体中更为明显，净效应是，在温度较高的等离子体中，颗粒的寿命可能比近似声波流模型预测的寿命稍微延长。推导了一个简单的注入深度标度规律，并对几种托卡马克的颗粒燃料速度要求进行了估计。
A revised neutral molecule ablation model is derived to describe the evaporation of a solid hydrogen pellet in a tokamak plasma. The approach taken is based on the theory of Parks, Turnbull, and Foster who postulate that a cloud of molecular hydrogen surrounding the pellet shields the surface from incoming energetic electrons and, in so doing, regulates the evaporation rate. This treatment differs from the earlier model in that the hydrodynamic behavior of the molecular cloud is analyzed without invoking the assumption that the flow of material away from the surface is sonic everywhere. Numerical solutions of the fluid dynamic equations, which include the effects of strong electron heating locally in the gas, reveal that the flow of material away from the pellet is initially retarded relative to the solution of Parks et al., and then rapidly accelerated and rarified. This behavior is more pronounced for higher temperature plasmas and the net effect is that pellet life times might be prolonged slightly at the higher temperatures over those predicted by the approximate sonic flow model. A simple injection depth scaling law is derived and estimates of pellet fueling velocity requirements are made for several tokamaks.