Overview of ITER physics deuterium-tritium experiments in JET
Overview of ITER physics deuterium-tritium experiments in JET
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DOI：
10.1088/0029-5515/39/2/307
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发表时间：
1999-02-01
期刊：
影响因子：
3.3
通讯作者：
Thomsen, K
中科院分区：
文献类型：
--
作者：
Jacquinot, J;Bhatnagar, VP;Thomsen, K
概述了与ITER运行模式直接相关的DT等离子体中的喷注实验结果。在从100：0到10：90的D：T混合气中和在氢等离子体中进行的实验表明，H模阈值功率与同位素质量近似成反比。匹配一些关键的无量纲参数：与热核实验堆的值匹配，热核实验堆形状和安全系数Q的相似性实验表明，全球能量限制时间实际上与同位素质量无关(类似于A(0.03+/-0.08))，其中II是类氢物种的原子质量。从总存储能量中减去边缘基座能量(其比例类似于A(0.57+/-0.2))导致等离子体核心中限制的类似A(-0.17+/-0.1)依赖关系？非常类似于陀螺-玻姆输运的预期(类似于A(-0.2))模型。观察到的边缘基座能量的标度与一个模型是一致的，在该模型中，边缘压力梯度在一定宽度的区域内以气球极限饱和，该区域的尺度为由边缘快离子的平均能量控制的离子极向拉莫尔半径。在ICRH和NBI放电中，给定输入功率的稳态总存储能量是相同的，尽管ICRH情况下边缘基座较低，这被ICRH中更多峰值功率沉积曲线所补偿。NBI放电的ELM频率较小；NBI放电和ICRH放电的ELM频率均随同位素质量的增加而减小。采用ITER形状、Q值为3.8T/3.8 mA、输入功率为22 mW的稳态I型Elmy H模放电，得到3.5T/3.8 mW的Q值约为0.18，并用ITER参数进行了外推。这里，Q是聚变输出功率与输入功率的比率。当等离子体密度超过Greenwald(n(GW))极限的0.75时，两种介质中的热Elmy H模约束显著降低，最大密度达到0.85N(GW)。在L模式下，密度极限随同位素质量的增加而减小，与代码预测的结果基本一致。对热核实验堆参考ICRH方案进行了评估。在喷注中可用的密度下，氚的二次谐波加热会产生强大的尾巴，并主要如预期的那样加热电子。在50：50D：T和氚为主的等离子体中，少数He-3表现出强烈的体离子加热，仅ICRH就能使离子温度高达13keV。在0 mW的脉冲氚等离子体中，对超过2.5的S产生了接近于0.22的稳态记录。
An overview of JET experimental results in DT plasmas directly relevant to ITER modes of operation is presented. Experiments in D:T mixtures varying from 100:0 to 10:90 and those carried out in hydrogen plasmas show that the H mode threshold power has an approximately inverse isotope mass dependence. Matching some of the key dimensionless parameters: to the ITER values, the ITER similarity experiments with ITER shape and safety factor q show that the global energy confinement time is practically independent of isotopic mass (similar to A(0.03+/-0.08)), where ii is the atomic mass of the hydrogenic species. Subtracting the edge pedestal energy (which scales as similar to A(0.57+/-0.2)) from the total stored energy leads to a similar to A(-0.17+/-0.1) dependence of confinement in the plasma core? very similar to that expected from the gyro-Bohm transport (similar to A(-0.2)) model. The observed scaling of the edge pedestal energy is consistent with a model in which the edge pressure gradient saturates at the ballooning limit over a region of width that scales as the ion poloidal Larmor radius governed by the average energy of the fast ions in the edge. The steady state total stored energy for a given input power in both ICRH and NBI discharges is the same despite the lower edge pedestal in the ICRH case, which is compensated for by more peaked power deposition profiles in ICRH. The ELM frequency is smaller with NBI; it decreases with isotopic mass in both NBI and ICRH discharges. A steady state, type I ELMy H mode discharge with ITER shape and q at 3.8 T/3.8 MA with an input power of 22 MW produced a Q approximate to 0.18 for 3.5 s and extrapolates well to ignition with ITER parameters. Here, Q is the ratio of fusion output power to input power. The thermal ELMy H mode confinement in both deuterium and tritium gas fuelled plasmas decreases significantly when the plasma density exceeds 0.75 of the Greenwald (n(GW)) limit, and the maximum density achieved is 0.85n(GW). In L mode, the density limit decreases with increasing isotope mass roughly in accordance with code predictions. ITER reference ICRH scenarios have been evaluated. Second harmonic heating of tritium at the densities available in JET produces strong tails and heats electrons predominantly as expected. The He-3 minority in 50:50 D:T and tritium dominated plasmas showed strong bulk ion heating leading to ion temperatures up to 13 keV with ICRH alone. Deuterium minority ion cyclotron heating in tritium plasmas at a pou er level of 0 MW produced steady state record values of Q approximate to 0.22 for more than 2.5 s.