Current-mode triple and quadruple Langmuir probe methods with applications to flowing pulsed plasmas
Current-mode triple and quadruple Langmuir probe methods with applications to flowing pulsed plasmas
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DOI：
10.1109/tps.2004.835520
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发表时间：
2004-10-01
影响因子：
1.5
通讯作者：
Kamhawi, H
中科院分区：
文献类型：
--
作者：
Gatsonis, NA;Byrne, LT;Kamhawi, H
在流动的、脉冲的、无碰撞的等离子体中，发展并实现了三重和四重朗缪尔探针的电流模式方法。电流模式方法涉及偏置所有探针电极，并且需要测量探针电流，提供电子温度、电子密度以及离子速度与最可能热速度的比率。发展了单组分、双温度、无碰撞等离子体的电流模理论。探针的电流收集模型与流动和半径与德拜长度之比为5小于或等于r（p）/ lambda（D）小于或等于100对齐，考虑了有限鞘效应，而对于r（p）/ lambda（D）> 100，电流收集基于薄鞘假设。垂直探头的离子电流假设为薄鞘层，并作为离子速度比的函数给出。给出了求解非线性电流模方程的数值方法，并进行了灵敏度和不确定性分析。实验中使用的等离子体源是实验室特氟龙脉冲等离子体推进器，在5、20和40 J的放电能量下工作，脉冲持续时间为10-15 μ s，烧蚀20-50 μ g/脉冲。电流模式的三重和四重探针测量等离子体源的羽流在不同的位置。双探针和电流模式探针测量之间的广泛比较验证了新方法。
A current-mode method for triple and quadruple Langmuir probes was developed and implemented in flowing, pulsed, collisionless plasmas. The current-mode method involves biasing all probe electrodes, and requires the measurement of probe currents providing the electron temperature, the electron density, and the ratio of ion speed to most probable thermal speed. The current-mode theory is developed for a single species, two-temperature, collisionless plasma. The current collection model for a probe aligned with the flow and radius to Debye length ratios of 5 less than or equal to r(p) / lambda(D) less than or equal to 100 accounts for finite-sheath effects while for r(p) / lambda(D) > 100, current collection is based on the thin-sheath assumption. The ion current to the perpendicular probe assumes a thin-sheath and is given as a function of the ion speed ratio. The numerical procedure for the solution of the nonlinear current-mode equations, as well sensitivity and uncertainty analysis are presented. The plasma source used in the experiments is a laboratory Teflon pulsed plasma thruster, operating at discharge energies of 5, 20, and 40 J, with a pulse duration of 10-15 mus, ablating 20-50 mug/pulse. Current-mode triple and quadruple probe measurements obtained at various locations in the plume of the plasma source are presented. Extensive comparisons between double probe and current-mode probe measurements validate the new method.