Comparison of sheath thickness measurement methods using cutoff probe

The cutoff probe is commonly used for electron density diagnostics, and various methods have also been developed to apply it for sheath thickness estimation. However, the accuracy and applicable regimes of each method have not yet been fully verified. in this study, we compare two methods of estimating sheath thickness using a cutoff probe under various plasma conditions. The results from each method were compared with theoretical values based on the Child–Langmuir law. Through this comparison, we identified the method that more accurately reflects the theoretical sheath model. This work provides insight into selecting effective approaches for sheath diagnostics using cutoff probes.