Automated analysis of Langmuir probe traces using nonlinear regression

Abstract

This paper presents a simple, quick and effective automation of the analysis of Langmuir probe traces. A nonlinear regression method was used to obtain important plasma parameters. The algorithm utilizes single and double exponential models for the electron populations of the plasma system. The sensitivity of the algorithm to user input values was tested using a benchmark simulated data. The algorithm was also tested with an experimental data for the single exponential model. Care should be taken in choosing the boundary for the ion current fitting as it affects all the output parameters. Also, the algorithm was found to be sensitive to the choice of the right bound for the window for the nonlinear regression. Taking these into account, the approach was found to give satisfactory results.