Continuous wavelet transform based time-scale and multi-fractal analysis of the nonlinear oscillations in a hollow cathode glow discharge plasma

TL;DR

This paper applies continuous wavelet transform techniques to analyze nonlinear oscillations in a glow discharge plasma, revealing scale shifts, nonlinearity, chaos, and multifractal properties of the fluctuations.

Contribution

It introduces a wavelet-based method for detailed time-scale and multifractal analysis of plasma fluctuations, highlighting nonlinear and chaotic behaviors.

Findings

Detection of nonlinear behavior through scale shift analysis

Identification of nonlinearity and chaos from ridge plots

Multifractal spectra vary with discharge voltage, indicating complexity

Abstract

Continuous wavelet transform (CWT) based time-scale and multi-fractal analyses have been carried out on the anode glow related nonlinear floating potential fluctuations in a hollow cathode glow discharge plasma. CWT has been used to obtain the contour and ridge plots. Scale shift (or inversely frequency shift) which is a typical nonlinear behaviour, has been detected from the undulating contours. From the ridge plots, we have identified the presence of nonlinearity and degree of chaoticity. Using the wavelet transform modulus maxima technique we have obtained the multi-fractal spectrum for the fluctuations at different discharge voltages and the spectrum was observed to become a monofractal for periodic signals. These multi-fractal spectra were also used to estimate different quantities like the correlation and fractal dimension, degree of multi-fractality and complexity parameters. These estimations have been found to be consistent with the nonlinear time series analysis.