Ion Temperature Measurement in a Flowing Collisionless Plasma Using an End Effect of Cylindrical Langmuir Probes.

摘要

An experimental verification of the end effect theory of long cylindrical Langmuir probes in a high-speed collisionless plasma flow is reported. This effect is observed as a sharp departure from the predicted infinite probe current when a strongly negative probe is aligned with the flow. Both the height and the width of the ion current peak measured about the zero-degree attitude are strongly sensitive to ion temperature. The effect is verified for a mesothermal argon plasma with probe radius to Debye length ratio 0.005 < epsilon < 0.5 and for ion to electron temperature ratios close to unity.