Testing nonlocal models of electron thermal conduction for magnetic and inertial confinement fusion applications
Testing nonlocal models of electron thermal conduction for magnetic and inertial confinement fusion applications
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DOI：
10.1063/1.5001079
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发表时间：
2017-09-01
影响因子：
2.2
通讯作者：
Ridgers, C. P.
中科院分区：
文献类型：
--
作者：
Brodrick, J. P.;Kingham, R. J.;Ridgers, C. P.
三个模型的非局域电子热输运在这里进行了比较，对弗拉索夫-福克-普朗克（VFP）代码，以评估其准确性的情况下，相关的惯性聚变黑腔和托卡马克刮削层。测试的模型是（i）使用最初由Ji、Held和Sovinec [Phys. Plasmas 16，022312（2009）]开发的特征向量积分闭合（EIC）的基于矩的方法;（ii）Dimits、Joseph和Umansky [Phys. Plasmas 21，055907（2014）]的非傅立叶朗道流体（NFLF）模型; Schurtz，Nicolai和Busquet的[Phys. Plasmas 7，4238（2000）]多群扩散模型（SNB）。我们发现，虽然EIC和NFLF模型准确地预测阻尼率的小幅度的温度扰动（在10%以内，在中度碰撞），他们高估了高达35%的峰值热流，并没有预测预热在更相关的情况下，有一个大的温差。然而，如果注意平均自由程的定义，SNB模型与后一个问题的VFP结果更一致。我们第一次提出了一个比较的SNB模型与VFP代码的黑腔相关的问题与非均匀电离，并表明，该模型高估了热流的氦气-尽管预测峰值热通量在16%以内，但填充因子类似于2。(C)2017年作者。
Three models for nonlocal electron thermal transport are here compared against Vlasov-Fokker-Planck (VFP) codes to assess their accuracy in situations relevant to both inertial fusion hohlraums and tokamak scrape-off layers. The models tested are (i)a moment-based approach using an eigen-vector integral closure (EIC) originally developed by Ji, Held, and Sovinec [Phys. Plasmas 16, 022312 (2009)]; (ii) the non-Fourier Landau-fluid (NFLF) model of Dimits, Joseph, and Umansky [Phys. Plasmas 21, 055907 (2014)]; and (iii) Schurtz, Nicolai, and Busquet's [Phys. Plasmas 7, 4238 (2000)] multigroup diffusion model (SNB). We find that while the EIC and NFLF models accurately predict the damping rate of a small-amplitude temperature perturbation (within 10% at moderate collisionalities), they overestimate the peak heat flow by as much as 35% and do not predict preheat in the more relevant case where there is a large temperature difference. The SNB model, however, agrees better with VFP results for the latter problem if care is taken with the definition of the mean free path. Additionally, we present for the first time a comparison of the SNB model against a VFP code for a hohlraum-relevant problem with inhomogeneous ionisation and show that the model overestimates the heat flow in the helium gas-fill by a factor of similar to 2 despite predicting the peak heat flux to within 16%. (C) 2017 Author(s).