Ionization waves in the PK-4 direct current neon discharge
Ionization waves in the PK-4 direct current neon discharge
复制标题
PK-4直流氖放电中的电离波
DOI：
10.1088/1361-6595/abb955
复制
发表时间：
2020
影响因子：
3.8
通讯作者：
Hyde, Truell W
中科院分区：
文献类型：
--
作者：
Hartmann, Peter;Rosenberg, Marlene;Juhasz, Zoltan;Matthews, Lorin S;Sanford, Dustin L.;Vermillion, Katrina;Reyes, Jorge Carmona;Hyde, Truell W
PK-4系统是目前在国际空间站上运行的微重力尘埃等离子体实验。该实验利用氖或氩气体中的长直流放电。我们应用我们的二维粒子在细胞与蒙特卡罗碰撞放电模拟计算本地等离子体参数，作为未来的尘埃动力学模型的输入数据。模拟包括电子，Ne+离子，氖-m亚稳原子在氖气和它们的碰撞在固体表面，包括二次电子发射和玻璃壁充电。在机载光学成像的时间尺度上，阳性柱表现出稳定和均匀。另一方面，我们的模拟表明，在微秒时间尺度上，正柱是高度不均匀的：相速度在500 ms− 1和1200 ms− 1之间的电离波占主导地位。在这些波中，电场和带电粒子密度的振幅可以达到其平均值的10倍。我们的地面PK-4复制系统的实验完全支持的数值结果。在实验中，直流电流的方向可以交替，这已被发现有利于粉尘颗粒链的形成。我们讨论了如何高度振荡的等离子体环境有助于尘埃粒子链的形成可能的机制。
The PK-4 system is a micro-gravity dusty plasma experiment currently in operation on-board the International Space Station. The experiment utilizes a long DC discharge in neon or argon gases. We apply our 2D particle-in-cell with Monte Carlo collisions discharge simulation to compute local plasma parameters that serve as input data for future dust dynamics models. The simulation includes electrons, Ne+ ions, and Ne m metastable atoms in neon gas and their collisions at solid surfaces including secondary electron emission and glass wall charging. On the time scale of the on-board optical imaging, the positive column appears stable and homogeneous. On the other hand, our simulations show that on microsecond time scales the positive column is highly inhomogeneous: ionization waves with phase velocities in the range between 500 ms− 1 and 1200 ms− 1 dominate the structure. In these waves, the electric field and charged particle densities can reach amplitudes up to 10 times of their average value. Our experiments on ground-based PK-4 replica systems fully support the numerical findings. In the experiment, the direction of the DC current can be alternated, which has been found to favor dust particle chain formation. We discuss possible mechanisms for how the highly oscillatory plasma environment contributes to the dust particle chain formation.
DOI：
--
发表时间：
1964
期刊：
影响因子：
--
作者：
W. Davis
通讯作者：
W. Davis