微波单极子天线探针对等离子体密度的测量及修正

摘要

对一种新的诊断等离子体密度的方法--微波单极子天线探针的反射特性进行了详细的实验和数值研究,并与静电双探针测量结果进行比较,实验验证了两种测量结果能够较好地吻合.结合实验和数值研究,分析了电子碰撞项、鞘层以及等离子体密度不均匀性对测量结果的影响,并分别提出了鞘层修正和碰撞修正的方法,修正结果表明,在所给的实验条件中,即探针表面鞘层厚度小于1mm、气体压强小于200 Pa时,鞘层修正及碰撞修正均可被忽略,而随着气压的升高,碰撞加剧,或者在较厚的鞘层条件下,修正的效果将会逐步突显.另外,测量的空间分辨率受探针几何尺寸制约.%Based on the reflection characteristics, a monopole antenna used as a plasma density diagnostic tool was investigated experimentally and numerically.Compared with the measurement result obtained by Langmuir double-probe, the monopole antenna probe was a valuable measuring method.The electron collisional effect and sheath thickness effect were discussed and two methods were proposed for revising the effects of collision and sheath respectively.Based on the two methods, both collisional effect and sheath effect can be neglected in the experiment conditions, namely, the low gas pressure (＜200 Pa) and thin sheath thickness (＜ 1 mm).However, when collision increases with increasing pressure or when the sheath is thicker, the effects of the revision will be increasingly noticeable.Besides, the spatial resolution of the monopole antenna probe was limited by antenna length.