title: Digital smoothing of the Langmuir probe I-V characteristic.
abstract: Electrostatic probes or Langmuir probes are the most common diagnostic tools in plasma discharges. The second derivative of the Langmuir probe I-V characteristic is proportional to the electron energy distribution function. Determining the second derivative accurately requires some method of noise suppression. We compare the Savitzky-Golay filter, the Gaussian filter, and polynomial fitting to the Blackman filter for digitally smoothing simulated and measured I-V characteristics. We find that the Blackman filter achieves the most smoothing with minimal distortion for noisy data.
authors.affiliation: Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavk, Iceland.
authors.forename: F
authors.initials: F
authors.lastname: Magnus
authors.forename: J T
authors.initials: JT
authors.lastname: Gudmundsson