Analysis of Two Dimensional Velocity Space Structure of Ions in Simulated Divertor Plasma With High Angular

高角模拟偏滤器等离子体中离子二维速度空间结构分析

• 批准号: 14580520
• 负责人: FUJITA Hiroharu
• 金额: $ 1.79万
• 依托单位: Saga University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14580520/
• 关键词: High angular resolution analyzer; Simulated divertor plasma; Ion temperature; Ion energy distribution; Hole parameter; イオン2次元速度空間構造

One of important problems in divertor plasma is to reduce the heating load from internal plasma to divertor plate where the sputtering of the plate is frequently, occurred in nuclear fusion reactor. When the sputtering of the plate is discussed, it is important to clarify two dimensional behavior of energy and temperature of ions incident to the plate. In this work, measurement of two dimensional velocity distributions of ions has been performed in DC discharge plasma. Ion temperature measurement has been done in simulated divertor plasma using inductively coupled plasma. Energy distribution functions of ions incident to substrate biased negatively has also measured in electron cyclotron resonance microwave plasma. In these measurements, grid and directional analyzers were used. The interesting results on ion behaviors were obtained as follows.1.Measurement of ion two-dimensional velocity space structure by means of directional analyzerFor fundamental experiment on ion velocity distrib … More ution, two dimensional velocity distribution functions were measured in do discharge double plasma using directional analyzer which was consisted from capillary plate, retarding grid and ion collector. The analyzer has a high angular resolution of 1.4 degree. The two dimensional ion velocity space maps were estimated from velocity distribution functions obtained at all directions. It was confirmed that the directional analyzer could evaluate the spread on two dimensional ion velocity spaces.2.Development of stimulated divertor plasmaInductively coupled plasma (ICP) source where 3 turns helical antenna was wounded around glass tube with 3 cm, is used as one of the stimulated divertor plasma. ICP with electron 'density of 10^<12> cm^<-3> was obtained for optimum stimulated divertor plasma.3.Ion measurement in ICPIon measurement Ti was done comparing with electron temperature Fe in ICP under a divergent magnetic configuration. The dependency of the magnetic field and gas pressure on both of T_e and T_i was also studied. In the former case, T_i was found to decrease for ion hole-parameter hi【greater than or equal】3, while Te decreased drastically for electron hole-parameter h_e【greater than or equal】200 and saturated for h_e【greater than or equal】10^3. In the latter case, T_e in, a non-magnetized plasma (B=0) provides the same gas pressure tendency as the T_i at magnetic flux density B=575G, while Te at B=575 G decreased, gradually with the pressure.4.Measurement of energy distribution of ions incident to RF biased substrateTime averaged energy distribution functions of ions impacted in the rf-biased substrate have been investigated in ECR microwave plasma from the viewpoint of the ion plasma frequency. It was observed that TIIEDF has a bimodal profile for a wide range of f_<pi>/f_<b-> Here fpi and fb are ion plasma frequency and RF biased frequency, respectively. It was found that even for f_<pi>/f_b<<1, the bimodal profile was observed at high rf-biased voltages. It was revealed that the energy difference in TIIEDFs increased with increasing the rf-biased voltage for f_<pi>/f_b<1, while for f_<pi>/f_b>1, the energy difference decreased with increasing f f_<pi>/f_<b->. Less

偏滤器等离子体的重要问题之一是减少从内部等离子体到偏滤器板的热负荷，在核聚变反应堆中偏滤器板经常发生溅射。当讨论板的溅射时，重要的是澄清入射到板的离子的能量和温度的二维行为。在这项工作中，在直流放电等离子体中进行了离子二维速度分布的测量。使用电感耦合等离子体在模拟偏滤器等离子体中完成了离子温度测量。在电子回旋共振微波等离子体中也测量了入射到负偏压基底的离子的能量分布函数。在这些测量中，使用了网格和方向分析仪。获得了以下关于离子行为的有趣结果：1.利用定向分析仪测量离子二维速度空间结构为了离子速度分布的基础实验，利用由毛细管板、减速栅和离子收集器组成的定向分析仪测量了do放电双等离子体中的二维速度分布函数。该分析仪具有 1.4 度的高角分辨率。二维离子速度空间图是根据在所有方向上获得的速度分布函数来估计的。证实了定向分析仪可以评估二维离子速度空间上的扩散。2.受激偏滤器等离子体的研制采用在玻璃管上缠绕3cm长的3匝螺旋天线的感应耦合等离子体(ICP)源作为受激偏滤器等离子体之一。获得电子密度为10^12cm^-3的ICP以获得最佳受激偏滤器等离子体。3.ICP中的离子测量在发散磁配置下将ICP中的离子测量Ti与电子温度Fe进行比较。还研究了磁场和气压对 T_e 和 T_i 的依赖性。在前一种情况下，当离子空穴参数hi【大于或等于】3时，T_i下降，而当电子空穴参数h_e【大于或等于】200时，Te急剧下降，当h_e【大于或等于】10^3时，Te饱和。在后一种情况下，非磁化等离子体 (B=0) 中的 T_e 提供与磁通密度 B=575G 时的 T_i 相同的气压趋势，而 B=575G 时的 Te 随着压力逐渐减小。 4. 入射到 RF 偏置衬底的离子能量分布的测量在 RF 偏置衬底中撞击的离子的时间平均能量分布函数已在 从离子等离子体频率的角度来看ECR微波等离子体。据观察，TIIEDF 在较宽的 f_<pi>/f_<b-> 范围内具有双峰分布，其中 fpi 和 fb 分别是离子等离子体频率和 RF 偏置频率。研究发现，即使对于 f_<pi>/f_b<<1，在高射频偏置电压下也可以观察到双峰分布。结果表明，对于 f_<pi>/f_b<1，TIIEDF 的能量差随着射频偏置电压的增加而增加，而对于 f_<pi>/f_b>1，能量差随着 f_<pi>/f_<b-> 的增加而减小。较少的

项目成果

H.Fujita: "Annular Profile of Dust Density near RF-Powered Electrode in a Capacitively Coupled Plasma"Japanese Journal Applied Physics. 41・4. 2195-2198 (2002)

H.Fujita：“电容耦合等离子体中射频供电电极附近的灰尘密度的环形分布”日本应用物理学杂志 41・4（2002 年）。

藤田寛治(分担): "マイクロ波プラズマの技術(プラズマ調査専門委員会編)"オーム社. 257 (2003)

Hiroharu Fujita（撰稿人）：“微波等离子体技术（等离子体研究专家委员会编辑）”Ohmsha 257（2003）。

H.Fujita: "Observation of an Inductively Coupled RF Discharge with One-Turn Internal Antenna"Japanese Journal Applied Physics. 41・5. 3114-3119 (2002)

H.Fujita：“用一圈内部天线进行感应耦合射频放电的观察”日本应用物理学杂志 41・5 3114-3119（2002 年）。

Y.Ohtsu, K.Yoshinaga, H.Fujita: "Time-Averaged Energy Distribution Function of Ions Impacted on an RF-biased Substrate in Electron Cyclotron Resonance Microwave Plasm"Japanese Journal Applied Physics. Vol.42. 7552-7556 (2004)

Y.Ohtsu、K.Yoshinaga、H.Fujita：“电子回旋共振微波等离子体中撞击 RF 偏置基底的离子的时间平均能量分布函数”日本应用物理学杂志。

Y.Ohtsu: "Time-averaged energy distribution function of ions impacted on an rf biased substrate in ECR microwave plasma by means of a conventional energy analyzer"Japanese Journal Applied Physics. 43・1. 328-331 (2004)

Y.Ohtsu：“通过传统能量分析仪在 ECR 微波等离子体中撞击射频偏压基底的离子的时间平均能量分布函数”，日本应用物理学杂志 43・1（2004 年）。