Differential pumping requirements for the light-ion helicon source and heating systems of Proto-MPEX
Differential pumping requirements for the light-ion helicon source and heating systems of Proto-MPEX
复制标题
Proto-MPEX 的轻离子螺旋源和加热系统的差分泵浦要求
DOI：
10.1063/1.5001519
复制
发表时间：
2018
影响因子：
2.2
通讯作者：
J. Rapp
中科院分区：
文献类型：
--
作者：
J. Caneses;P. Piotrowicz;T. Biewer;J. Caughman;R. Goulding;N. Kafle;J. Rapp
在原材料等离子体暴露实验线性装置中，高密度氘螺旋等离子体（>3 × 10 19 m−3）的电子和离子加热物理正在研究中。理论估计表明，有效的加热，放电与非常低的中性气体含量（10.1帕）的加热部分，需要尽量减少碰撞损失和电荷交换与中性粒子的相互作用。然而，这种要求通常与高密度轻离子螺旋源中常用的中性气体压力（1-2 Pa）不兼容。为了满足这些相互竞争的要求，需要差分泵浦技术。在本文中，结果表明，生产高密度放电（2-6 × 10 19 m−3）与非常低的中性气体含量（75%）在加热部分。结果表明，最佳的燃料加注位置是等离子体源的上游。我们详细阐述了产生这些排放必须考虑的关键方面：（1）加燃料位置、射频脉冲长度和磁场配置，（2）气体注入的流速和定时，高密度氘螺旋等离子体的电子和离子加热物理（>3 × 10 19 m−3）在原型材料等离子体暴露实验线性装置中的应用正在研究中。理论估计表明，有效的加热，放电与非常低的中性气体含量（10.1帕）的加热部分，需要尽量减少碰撞损失和电荷交换与中性粒子的相互作用。然而，这种要求通常与高密度轻离子螺旋源中常用的中性气体压力（1-2 Pa）不兼容。为了满足这些相互竞争的要求，需要差分泵送技术。在本文中，结果表明，生产高密度放电（2-6 × 10 19 m−3）与非常低的中性气体含量（75%）在加热部分。结果表明，最佳的燃料加注位置是等离子体源的上游。我们详细阐述了必须考虑的关键方面。
The physics of electron and ion heating of high-density deuterium helicon plasmas (>3 × 10 19 m−3) in the Proto-Material Plasma Exposure Experiment linear device are under investigation. Theoretical estimates indicate that for efficient heating, discharges with very low neutral gas content ( ≪0.1 Pa) in the heating sections are required to minimize collisional losses and charge exchange interactions with neutrals. However, this requirement is typically not compatible with the neutral gas pressures (1–2 Pa) commonly used in high-density, light-ion helicon sources. To satisfy these competing requirements, differential pumping techniques are needed. In this paper, results are presented that demonstrate the production of high-density discharges (2–6 × 10 19 m−3) with very low neutral gas content ( 75%) in the heating sections. Results indicate that the best fueling location is upstream of the plasma source. We elaborate on the key aspects that must be considered to produce these discharges: (1) fueling location, radio-frequency pulse length, and magnetic field configuration, (2) flow rate and timing of the gas injection, and (3) use of conductance-limiting elements.The physics of electron and ion heating of high-density deuterium helicon plasmas (>3 × 10 19 m−3) in the Proto-Material Plasma Exposure Experiment linear device are under investigation. Theoretical estimates indicate that for efficient heating, discharges with very low neutral gas content ( ≪0.1 Pa) in the heating sections are required to minimize collisional losses and charge exchange interactions with neutrals. However, this requirement is typically not compatible with the neutral gas pressures (1–2 Pa) commonly used in high-density, light-ion helicon sources. To satisfy these competing requirements, differential pumping techniques are needed. In this paper, results are presented that demonstrate the production of high-density discharges (2–6 × 10 19 m−3) with very low neutral gas content ( 75%) in the heating sections. Results indicate that the best fueling location is upstream of the plasma source. We elaborate on the key aspects that must be cons...