Wavelet analysis as a nonstationary plasma fluctuation diagnostic tool
- Univ. of Texas, Austin, TX (United States). Fusion Research Center
Analysis of nonstationary plasma fluctuation data has been a long-time challenge for the plasma diagnostic community. For this reason, in this paper the authors present and apply wavelet transforms as a new diagnostic tool to analyze nonstationary plasma fluctuation data. Unlike the Fourier transform, which represents a given signal globally without temporal resolution, the wavelet transform provides a local representation of the given signal in the time-scale domain. The fundamental concepts and multiresolution properties of wavelet transforms, along with a brief comparison with the short-time Fourier transform, are presented in this paper. The selection of a prototype wavelet or a mother wavelet is also discussed. Digital implementation of wavelet spectral analysis, which include time-scale power spectra and scale power spectra are described. The efficacy of the wavelet approach is demonstrated by analyzing transient broadband electrostatic potential fluctuations inside the inversion radius of sawtoothing TEXT-U plasmas during electron cyclotron resonance heating. The potential signals are collected using a 2 MeV heavy ion beam probe.
- OSTI ID:
- 423062
- Report Number(s):
- CONF-960634--
- Country of Publication:
- United States
- Language:
- English
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