Determination of Plasma Potential from the Langmuir Probe Trace Using Bi-orthogonal Wavelet Transform

Abstract

In automatic analysis of the Langmuir probe (LP) data, the determination of the plasma potential with less operator inputs improves the accuracy and consistency of the analysis. In this study, a new algorithm was utilized to determine the plasma potential using bi-orthogonal wavelet transform. In spite of the high noise level of the probe data, the bi-orthogonal wavelet transform of the first order differentiated LP data provides the peak clearly. The plasma potential can be determined from the peak of the differentiated data in a mathematical manner and the data process regions are partitioned with respect to the plasma without any operator inputs. The sensitivity of this algorithm was evaluated with artificial data including random noise.